The Ice King receives no end of sympathy from most fans, continually painting him as harmless and misunderstood. While he is a Jerkass Woobie with a Freudian Excuse, he still harasses, stalks, kidnaps, imprisons, mind-controls, and at one point mutilates around a dozen different women, all for the purpose of forcing them to "marry" him.
Ash, Marceline's Jerkass ex-boyfriend, who unlike this previous two is a completely straight example - he's good-looking, and that's his one positive attribute.
Even for being a Scrappy character, Lemongrab still has fans. He has a loud fanbase that often forgot just why everyone hates him so much. Even after being revealed he uses his mental illness as an excuse to be a jerkass to everyone (when Lemonjon got Empathy), eating and mutilating his own brother, and finally becoming a corpulentdictator, his fanbase still tries to get everyone to sympathize with him despite revelations showing he doesn't deserve it.
Many of the Fire Nation, especially Azula, and occasionally Zhao and Ozai. Sure, it's revealed that Azula has a Freudian Excuse towards the end, but that doesn't excuse her evil deeds, and Zhao and Ozai have no redeeming qualities whatsoever.
Azula gained some extra points on the Draco-meter by showing signs of actually being interested in romance, but just not knowing how it should be done because of her inner darkness eating her up. You don't have to ask the fandom twice.
It also doesn't hurt that The Search hinted that she might be redeemable after all, and showed that, while blown waaay out of proportion by her madness, she actually did have a solid basis to feel that she wasn't loved by her mother.
Sozin gets this treatment quite a bit, another case of his fans focusing on the "well-intentioned" and ignoring the "extremist" aspects of Well-Intentioned Extremist. They see nothing wrong with him wanting to spread the fire nation's glory, power, and advanced civilization with the rest of the world, which apparently justifies 100 years of war, the first act of which after disposing of the only man who could stop him was a complete genocide, and many other genocidal actions to follow.
Zuko got this treatment back when he was an Anti-Villain, with many fans saying all his wrong actions can be excused because of his angsty backstory and conflicted nature. Mike and Bryan themselves have brought this up in commentary for episodes such as "The Warriors of Kyoshi" and "The Beach" that, as sympathetic as Zuko is, he's not supposed to be justified in his bad actions, and in fact a big part of his Character Development is learning that he needs to take responsibility for his bad actions. This internal struggle of good and evil, which has still crept up even after his Heel-Face Turn, is kind of the entire point of his character.
Long Feng and his Dai Li are sometimes given this treatment, with their Orwellian methods and repression of Ba Sing Se painted as the act of true patriots who were compelled to do whatever it took to keep their city safe.
Dag from Barnyard could be justified by the fact that coyotes have to eat, but did he really have to antagonize that one farm in particular, kill Ben, make Otis feel small, and attack during the day when no one was expecting them?
Fanfics about Batman: The Animated Series often depict the Rogues Gallery as a fun-loving bunch of lovable misfits who are unfairly and brutally harassed by the humorless Caped Crusader. Never mind that even in the kids' show's context, most of the Rogues were originally apprehended for attempting ruthless murders on hapless civilians for imagined or exaggerated slights, and that when Batman was put on trial for supposedly creating his foes, the jury of villains found him not guilty in the end and decided that they were responsible for their own messed-up behavior. Then they tried to kill Batman anyway.
The Penguin also gets the Jerkass Woobie treatment: it's easy to feel sorry for a short, funny-looking man who gets looked down on by many people. This is particularly the case in the early episode "Birds of a Feather", where it's shown that he commits crimes (all of them as nonviolent as he can possibly make them, unless he gets really angry) either simply for fun or to win some respect for himself. That episode even opens with him speaking politely and amicably to a man he's just tied up and is robbing. It's clear, at least in these early appearances, that the Penguin doesn't want to hurt anyone; it's just that he feels being a crook is what he was meant to do in life.
After Alien Force made Kevin a good guy, this trope went to his new Evil Counterpart Darkstar instead. Darkstar is a pure creepy Jerkass stalker who had no problem with manipulating innocent schoolgirls and turning them into zombies to increase his powers and is never portrayed as sympathetic in any way, even during his Enemy Mine with the heroes. Other villains like Vilgax, Charmcaster, Albedo, and the Forever Knights at least have varying shades of nobility and moral ambiguity to them. Darkstar has none.
Lahwhinie from the Chip 'n Dale Rescue Rangers episode "Gadget Goes Hawaiian" is Gadget's Evil Twin. Period. At least in canon. But for some fans, she is Gadget minus her quirks and geek attitude and lack of social skills, but plus a dress and make-up and actual passion, and sometimes have her do a more or less spectacular Heel-Face Turn.
Code Lyoko: William's long-term possession by XANA has definitely increased his fanbase, although the emphasis is more on curing him than on loving him for/despite being evil.
Vlad Masters/Plasmius based his life around revenge for an accident and the title character's father "stealing" his one true love Maddie. He uses deception and mind control to amass his fortune and uses it and his ghost powers to attempt murder and cause mayhem, which he somehow thinks is a good way to get Maddie to fall in love with him and Danny to consider him as a better father than Jack. Yet because all he wants, essentially, is to be loved, numerous fans ignore that he's a selfish, maniacal narcissist.
Ember McLain gets this treatment, mostly for her loss, but some fans think that her song was about her suicide after being cheated on by her Bastard Boyfriend.
Mandark from Dexter's Laboratory In the show he's an Evil Genius and the closest this series has to a Big Bad. Try explaining that to fangirls who portray him as a sweet nerdy boy who just wants Dee Dee to love him.
Mozenrath from Disney's Aladdin: The Series. For many fans, his hotness and him being one of the better written and more threatening villains in the show outweigh the fact that he's a sadistic psycho, turned his father-figure into a zombie, devoted his life to ruining Aladdin's, and wants to take over Agrabah just "because it's there". The belief that Mozenrath was intended to be Aladdin's brother seems to be an unfortunate (and persistent) side-effect of this trope.
Duck Dodgers deconstructs this trope in one episode. There's a villain called the Magnificent Rogue who basically terrorizes people, yet is worshipped because he's so attractive. Even when he flat out admits that he is indeed insane. Porky snaps out of it and ultimately thwarts his plot. IQ also states that being beautiful doesn't give you the right to terrorize people. It could easily be trying to mock this trope.
May Kanker is often seen as a sympathetic Woobie and the Token Good Teammate of the Kanker sisters (a trio of bullies/molesters and the main villains of the show). True, the way her sisters treat her sometimes puts her on The Woobie territory, but when it comes to other people, she's just as cruel as them. Yet, some people would rather believe she wouldn't hurt a fly and she's just oppressed by Marie and Lee.
Her sister Marie, being the prettiest Kanker, usually gets the free pass from fandom, alternatively given a Freudian Excuse, similar to May's example above.
Norm from The Fairly Oddparents gets this bad. He's often portrayed as The Woobie, locked up in his lamp and was forced to serve several masters like Timmy. This is ignoring the fact that he is a Card CarryingJerkass and such a Jackass Genie that he was that page's picture. Also, he had tried to sell Timmy (who was originally apathetic toward Norm) on the prospect of having a genie, and the fact that he plans to destroy Canada once he's free should erode his sympathy.
Vicky is a destructive, abusive sociopath, but so many of her fans go to incredible lengths to justify or outright ignore these traits. Others simply fabricate a Freudian Excuse for her out of thin air, despite being repeatedly established that she has no such excuse, and indeed is the Freudian Excuse for several other characters, Timmy included.
Anti-Cosmo who's Cosmo's evil counter part, has been seen as a fairy who simply wants his own godchild, baring the fact he has made several attempts on conquering or destroying Fairy World and Earth.
Stewie tends to get sympathetic treatment in later episodes, largely due to putting up with Brian's selfish egotism and his Comedic Sociopath parents, disregarding the fact that even following his Flanderization, Stewie is often portrayed as a sadist who tries to kill his mother and puts Brian through all sorts of painful stunts for petty slights or even just to see if he can. (eg, giving him two gangster style beatings for overdue gambling fees or travelling in time to sabotage every meaningful point in his life over a gay joke).
Lois may qualify. Some of her defenders usually try to excuse her abuse towards Meg by saying that because other characters are cruel to Meg, that justifies her abuse. While it's true that other characters are cruel to Meg, the only reason Lois is vilified for it while Peter isn't is because she is the smarter of the two. Not to mention she's Meg's mother.
Hexxus, the Spirit of Destruction and pollution embodied in Ferngully The Last Rainforest gets this even though he's trying to level a rainforest full of plant and animal life as well as sentient fairies that depend on its existence to survive. It doesn't help that the movie is Anvilicious, the protagonists (save maybe for BattyKoda) are bland and rather uninteresting, and Hexxus himself is voiced by Tim Curry, with all the implications this entails. And he gets one of the best Villain Songs of all times.
Demona from is often a victim of this. While the character is definitely a three-dimensional villain, and you understand where she is coming from, a lot of fanfic authors spin this off into either being an apologist or completely re-writing the character to the point where she is Demona in name only. Add in the fact that she's already somewhat sympathetic by design and there you go. Usually, her daughter Angela will either wave a finger in Demona's face, and Demona magically gives up her hatred to have a relationship with her, or Demona magically falls in love with a human and sees that humans are not all bad. A lot of the time, Goliath is portrayed as an evilmisogynist. Generally, most of these fanfics are just an excuse to get Demona naked, and some authors have admitted that canon Demona is too difficult to write. Word of God states that Demona will still be plotting against humanity long after Angela and most of the cast are dead.
While Xanatos does get a whole slew of Pet the Dog moments and arguably evolves into an Anti-Villain by the end, he still commits a lot of ruthless or downright evil acts (especially early on) and never seriously regrets any of them (except maybe creating Thailog). There are nonetheless a disturbing amount of fans who portray Xanatos as little worse than a brilliant trickster, with more than one declaration that he isn't really evil or villainous. This probably wouldn't happen half as often if he didn't look like a physically-idealized Jonathan Frakes.
Rounding out the trifetica of the show's major villains is Macbeth. He's easily the most sympathetic even in canon- he's as tragic as Demona but not a tenth as vicious, and as affable as Xanatos without being nearly as manipulative- and he has an old-school warrior's sense of honor, but his fans have a definite tendency to treat him as a Hero Antagonist, which several of his actions (notably deciding to use Broadway- with whom he had no personal quarrel- as target practice for newly-acquired spells) show he's not. Per Word of God, he's an ends-justify-the-means kind of guy, and his ends are pretty questionable on their own. Character Development, however, does end up moving him into Hero Antagonist territory by the end of the series.
The only recurring villains who aren't in some way sympathetic are Tony Dracon and Sevarius, and they sometimes get the DILP treatment.
Breach. She isn't without sympathetic qualities, but sometimes people forget that she's completely insane and has happily kidnapped people to use them as toys in her "playhouse," throwing them away when she gets bored of them.
Murdoc of the Gorillaz is often seen this way, despite being a canonically alcoholic, exhibitionist, verbally and physically abusive megalomaniac. The trope is even employed in-universe, since despite many of these traits being publicly known, Murdoc does not lack for bedmates.
Bill Cipher, who is implied to be the Big Bad of the entire series, he is a living embodiment of the Illuminati symbol and he has psychotic behavior but fans love him. He is often drawn as a sexy man with one eye covered and dapper clothes who is sometimes shipped with Dipper or Mabel. When the episode "Sock Opera" where he possesses Dipper's body debuted, fans started fawning over "Bipper" and outright calling him sexy even though he tried to kill Mabel.
The episode "Soos and the Real Girl" introduced Giffany who is a sentient Dating Sim character. She is a Yandere who is implied to have killed her developers and tried to kill the people who played her, she also tries to force Soos to upload his brain to her system so they can be together forever. Many people found her cute and sexy and were even attracted to her yandere tendencies since she "proved" she was willing to go a long way for love, even if it meant coercing and abusing the person she "loved."
Zim from Invader Zim. It turns out all those ridiculous failed plans? They mean nothing; Zim is really a totally badass mastermind. But don't worry, he's not really evil; he would seriously regret destroying humanity, and would probably give it up if a kind-hearted human or Irken girl would just show him some love. Oh, and also, isn't Dib just such abastard for trying to stop him so much? There's a bit of this for other Irkens too, particularly the Tallests. Apparently galactic conquest and repeated genocide and enslavement of the survivors is a-okay.
Some of the fans have tried to justify this by pointing out their motives: Zim trying to impress the other Irkens especially the Tallests, Dib wanting to prove to everyone he was right about the aliens and look like the hero; forgetting that trying to impress someone, although sympathetic, isn't moral nor is enough to justify trying to destroy humanity and Take Over the World and that wanting to look like the hero is the exact same thing just more specific.
Gaz. Simply put, she's a selfish, abusive, and greedy brat with absolutely no redeeming qualities, yet many fans praise her as "the smartest character on the show" and call her a no-nonsense badass. This is especially baffling when you consider that not only does she refuse to risk her life for anyone but herself, but that she only goes after people who are much weaker and for petty reasons.
Amon. He's the charismatic leader of the Equalists, and just wants to bring about equality between benders and non-benders by ending all bending. Like certain protest movements, he has absolutely no problem harming the very people he claims to be helping. He's so charismatic, in fact, that he's even managed to convince some of the fans.
Tahno, while eventually becoming somewhat sympathetic after Amon takes his bending and leaves him a broken man, had fans wishing he could give them "private lessons" even when he was a total Jerkass.
Season 4 gives us Kuvira. She desperately wanted to save the Earth Kingdom from falling into anarchy after The Earth Queen's assassination. To that end, she usurped power from the reigning Prince Wu and reformed the kingdom into the Earth Empire. Like Amon, she is extremely charismatic and can justify her actions with arguments so reasonable that even the heroes begrudgingly agree she has a point. So charismatic is she that even some of the fandom will defend her by saying that she's just doing what she thinks is right, even when it's revealed she is throwing those not of Earth Kingdom decent into labor camps. The fact that the series finale portrays her as a Woobie, Destroyer of Worlds and gives her a Freudian Excuse to further humanize her only reinforced this sentiment.
RS-Protoman is arguably not as bad as most of the examples on this page, but some fans seem to think that his switching alliances would instantly rid him of his less pleasant traits. (Possibly so they can offload them to their idealizedversion of RS-Bass)
Gilda the Griffon from "Griffon the Brush-Off" is an obnoxious bully who thinks all the ponies of Ponyville (except her old friend Rainbow Dash) are "lame-o", and who literally scares Fluttershy to tears at one point. When her true colors are exposed at a party thrown by Pinkie Pie in an effort to get her to lighten up, screaming her head off at her so-called best friend and refusing to take her own medicine, she's quick to turn against Dash for being a "flip-flop" by sticking up for the other ponies, and leaves town in a huff. Fans were quick to portray her as a Jerkass Woobie wracked with guilt and self-hatred over alienating her oldest and best friend.
Trixie from "Boast Busters" had fans protesting she was just a traveling entertainer (true) whose audience was being unnecessarily mocking and hostile, that she was justified in humiliating Applejack, Rarity, and Rainbow Dash in front of their friends and neighbors, and that she was unjustly punished at the end of the episode, largely ignoring that she's a boastful, lying egomaniac both on- and off-stage. She did seem guilty about one of her lies indirectly leading to an Ursa Minor attacking Ponyville, but after the threat is dealt with she's right back to being all bluff and bravado.
At the end of "Magic Duel" though, Trixie does legitimately have a Heel-Face Turn and even renames herself as "The Great and Apologetic Trixie". Funnily enough, the reason she initially stated for her revenge (having her reputation and livelihood destroyed) were the exact same things her fans complained about.
Nightmare Moon (Princess Luna's Superpowered Evil Side created from the jealously over ponies being more fond of Celestia's day and sleeping through Luna's night) gets this a lot from fans that see Celestia as a tyrant, treating her as just wanting to free Equestria from Celestia's rule, despite Luna herself admitting that what she did was wrong and becoming The Atoner in canon.
Fans latch onto the Flim-Flam Brothers' stylishness, catchysong, and that their Super Speedy Cider Squeezy 6000 can actually produce quality cider. The fact that they're also a pair of aggressively greedy jerks who tried to completely and utterly drive the Apples out of business and gloated about it when they seemingly succeeded, and who are perfectly willing to sacrifice any semblance of quality in the name of quantity, tends to escape the minds of these fans.
Queen Chrysalis. "She just wanted to feed her children!" say the fans. While she did mention feeding her subjects, she put more focus on gathering power for herself, while laughing cruelly, and then proceeds to enslave all of Canterlot; she doesn't display the slightest shred of remorse for any of her actions and seems entirely incapable of empathy. There is also the fact that there is absolutely no canon mention or evidence whatsoever that the changelings minions are her children; it is merely popular fanon often used as a cheap tool by fanfiction authors in order to cloy as much sympathy as they possibly can from the readers.
Even King Sombra gets some. One theory has it that he was in love with Princess Luna and that her rejection of him made him turn to evil. Hilariously enough, this almost exactly parallels a theory about the aforementioned Discord and Princess Celestia, only with even less basis in canon. At least Discord and Celestia seem to know each other pretty well, there is no indication Sombra was involved any with Luna.
Lightning Dust is a sociopath who clearly didn't care at all that her reckless behavior very nearly got the Mane Six killed, cares solely about her own advancement, and even cracked a joke about the aforementioned near-disaster when Rainbow Dash calls her out on it. And yet, an alarming amount of viewers actually sympathise and woobify her, to the point that they demonize Rainbow Dash and Spitfire for "crushing her dream", despite the fact that Dust brought her downfall entirely on herself.
Prince Blueblood also receives sympathy from fans. They claim that he was "seen in the wrong by fans" for expecting chivalry from Rarity and that Rarity was just a gold-digger that Blueblood was trying to shake off, forgetting the fact that he's a rude, narcissistic, stuck-up, selfish, and spoiled jerkass who insulted Apple Jack's food and used Rarity as a pony shield to protect himself from flying cake, and not apologizing for his actions after Rarity called him out on his behavior.
Silver Spoon, the Beta Bitch to Diamond Tiara's gets a large amount of fan sympathy. On the show she's portrayed as a follower, but fans forget the fact that she's a willing accomplice to Diamond Tiara. Many fans on deviantart like to portray her as a Beleaguered Assistant to Diamond Tiara and have Silver Spoon often question how much their Villainous Friendship means. Silver Spoon can resist peer pressure, so this doesn't make her any better or worse than Diamond Tiara. Fanon Silver Spoon will express remorse when the CMC are bullied, and the one Pet the Dog moment she had in canon is treated like an everyday occurrence.
Rico. Okay, so he's not evil, but he is a loose cannon who needs to be kept under tight control. All that craziness is very often tossed aside in the interests of pairing him up with whichever penguin the author chooses.
King Julien. He's not evil, but he is a jerk. Again, it's abandoned for the purposes of bedding him down with Skipper or Marlene. The weird thing is, the movie, while he's not all that nice, he at least is concerned for his subjects, and demonstrates sincere gratitude toward Alex and the others, but is listed under Jerkass. While in the series he's abusive to Mort and Maurice, malicious toward the Penguins for the sake of it, rude in general and self-serving, with his few decent moments usually having at least partially selfish motivation, yet is listed under Jerk with a Heart of Gold, despite his negative qualities far outweighing his arguable positive ones.
The Rowdyruff Boys also tend to be toned down and glamorized into being misunderstood little boys who secretly long to be loved and in relationships with the Powerpuff Girls, the only ones who can tame them.
Princess also qualifies. Fans sympathize with her wanting to be a Powerpuff Girl and always getting rejected, ignoring the fact that she doesn't have superpowers or crime fighting experience, and only cares about being a Powerpuff Girl for the cosmetic reasons (being popular, powerful, and loved). They seem to ignore the fact that her jerkass personality is what keeps her from becoming liked by the girls and the fact that she's evil.
The Simpsons gives us Sideshow Bob. While his intelligence, menacing aura, and highbrow/Deadpan Snarker attitude combined with the perpetual clown-like mishaps to which he's subjected make him a cool and funny villain, there is a considerable fanbase determined to overlook the fact that his life revolves around murdering Bart and those who stand in the way of his murdering Bart, instead making him into an angster hiding his suffering under an antisocial exterior. Extra annoying in that they overlook the canonical explanation for any angst (his being Krusty the Klown's Butt Monkey for years), instead giving him a depressingly cliched tragic backstory.
The South Park fandom does this a lot, especially with characters like Cartman and Damien, who set Pip on fire and turned Kenny into a duck-billed platypus.
Plankton in SpongeBob SquarePants. It has been established that he's evil as he continued to try to take Krabs' secret formula in myriad ways. One episode even had him as a Jerk With A Heart Of Jerk with him saying "Being evil is just too much fun!" He's also been shown to be a big Jerkass with all his screaming and being angry. In The Movie, he had definitely crossed the Moral Event Horizon. But due to Flanderization and Took a Level in Jerkass on the parts of the main characters in the later seasons, some fans sided with Plankton, forgetting all the evil and nasty stuff he did in the earlier seasons. It sometimes seems that the writers forgot all the evil and nasty stuff he did in earlier seasons. Plankton's evil schemes once involved him trying to Take Over the World, but in later episodes all he wants to do is compete with the Krusty Krab. Not even destroy them or run them out of business, just compete. And unlike Krabs, he's never tried to torment someone into committing suicide and laugh about it.
Star Wars: The Clone Wars has some. Since Darth Maul was brought back in the fourth season, he has fans (as seen with the films). General Grievous, although he's a cold-blooded cyborg who killed hundreds of people receives this in spades. Young!Boba Fett also gets this, though in fairness, he's portrayed during his appearances as a sympathetic character.
While Superjail has a cast filled with characters that are corrupt or despicable to some degree, there are a few examples that tend to stand out when it comes to this:
Some tend to ignore the fact that while Alice has a bit of an unfortunate backstory, she's also described by the creators as a sadistic bully who intentionally abuses her power to get herself pleasure from the inmates. Any of her flaws can get easily glossed over for her to be simplified and painted as a saintly Woobie who just needs one good man (when fans aren't going in the other direction to demonize her for not returning Warden's feelings).
Lord Stingray gets a bunch of this treatment from certain fans, who feel as if he's been unfairly wronged and misunderstood for being imprisoned in Superjail. Some decide to depict him as physically attractive in order to play up suaveness to make him a viable partner for the Warden, if they don't go with outright Foe Yay.
The Twins are sometimes simplified into harmless innocent young men who just want to have fun in the jail, even though they're shown to take visible amusement in causing death and destruction. Sure, they start trouble to relieve boredom, but they aren't any less questionable in their morality than the rest of the cast.
Dr. Viper in SWAT Kats has a few fans despite being arguably the series' most sick, twisted and sadistic villain in his very first episode alone, and not being what would generally be considered attractive (even before he got mutated). Many early fanfics by one "Kikki Viper" revolved around the evil biochemist converting to Christianity, gaining a magical sword and saving the day. The fanfics have been given the MST treatment by many a SWAT Kats fan. Artist Ignigeno sexifies Viper while at least retaining his evil, sadistic personality.
Agent Bishop from Teenage Mutant Ninja Turtles 2003. Compared to the Shredder, he's a much more sympathetic and well intentioned villain, however while an undeniably a complex villain a lot of fans definitely romanticise him a little too much, especially considering the countless acts of murder, espionage, torture, and other dirty dealings that come close to, if not outright rival, the Shredder's. By the sixth season, set decades into the future, Bishop does renounce his evil ways to become one of the good guys, so he's not an entirely unsympathetic or irredeemable character. However, he achieved DILP status far before "Fast Forward" and there are still a disturbingly large amount of fans who prefer to sweep all his evil deeds under the rug and act as if he's nothing more than a heroic savior of the world with no flaws.
Slade, whose intelligence, competency and "cool" factor results in many fans ignoring the fact that he's a mind-raping adult who takes pride in stalking and fighting teenagers.
There's a subset of fans who think Terra should have been welcomed back with open arms and accepted as a permanent member of the team even after her stint as The Mole and The Dragon to Slade. They argue that none of it was her fault since Slade manipulated her (Terra herself makes this argument, but Beast Boy points out that she could have gotten out at any time but chose not too, and Terra ends up redeeming herself by accepting this fact and taking responsibility). She's a sympathetic Anti-Hero/Anti-VillainWoobie, Destroyer of Worlds to be sure, but to paint her as a blameless martyr is to miss the point of her character (of course, so's painting her as an irredeemable fiend like certain other fans like to do).
In The End of Ends, Terra has a realization in Chapter 8 that she should become a superhero again, and while it's going on, the narrator flat out tells us that Terra wasn't a bad person, but rather misunderstood.
Tygra from ThunderCats (2011), the reboot of the 1985 series. While he does have his share of redeeming qualities, is one of the good guys, and is confirmed by the creators to be a Jerkass Woobie instead of a tamed version of Big Brother Bully, a lot of his fan are a bit too willing to forgive him for and justify him leaving his adopted brother, Lion-O, to die twice, being somewhat of an unapologetic bigot, undermining Lion-O's authority and not supporting him on occasions.
The eponymous Tom and Jerry. While Tom is something of an Ineffectual Sympathetic Villain, fans have taken to downplaying Tomís flaws completely and treat Jerry as if he's the bad guy in all their altercations. The truth is that neither one is by any means innocent, being victim and provoker in almost equal measure, but Tom just gets the DILP pass because the writers worked so hard to depict that Jerry (who, at the time at least, automatically got audience sympathy by not being Tom) wasn't (and at that they let Tom win a lot of times he genuinely deserved it).
Duncan. It's invariably difficult to keep him in character seeing as his softer side overrules his bad-boy charm in the eyes of most fans. If you find a fanfic involving Duncan/Courtney, Duncan/Gwen, Duncan/anybody expect Draco in Leather Pants to come into play. (Although, those that ship him with Gwen do have some justified argument, she is the only one he is rather nice to.)
Gwen and Courtney also have this problem. Some fans on different sides of the CxDxG conflict believe the girl they support is blameless while demonizing the opposing character.
Most of the villains get this treatment. There are some fans who will portray Scott as kinder for the sake of DawnxScott, and even Mal is portrayed as having a shred of goodness in him in some fanon, despite being essentially the embodiment of chaotic evil.
Ezekiel is occasionally written as a sad, down-on-his-luck, poor woobie who doesn't actually want to be in the game, and gets a lot of flack from other characters who never forgive him for the comments back in the first season saying that guys are better than girls. By season three, and hinted at since the post-elimination special of the first season, it's clear that he's actually incredibly arrogant and there are more reasons for people to not like him becides his comments (which nobody really brings up to him). Seeing as he clings on to the jumbo jet after being thrown off and willingly stays there until becoming feral, it's also obvious that wanting to leave the game is something he would never do. And yet the innocent, pull-toque-over-his-eyes Ezekiel is still present after all of this, probably because the creator's attempts to make Ezekiel come off as a Jerkass with a huge ego backfired in his fan's eyes due to how little screentime he got.
Decepticons as a whole can be called Robots in Leather Pants. It's about a 50/50 split and Deceptifans tend to downplay their villainy a lot. Notable examples include Starscream, Ravage (especially after his upgrade in Beast Wars), BW Rampage, Animated, Starscream, Lockdown, Megatron, and more of Starscream.
It started with Beast Wars; technically, the Predacons are an oppressed minority on a "peaceful" Cybertron kept in the paranoid grip of the just-as-atrocious Maximal Elders, but their role is more akin to between-World Wars Germany, with Megatron and his troupe attempting to get them to put on the Reich. Like the Animated Decepticons, this goes unnoticed by fans, blinded by Beast!Megatron's Magnificent Bastardry, Tarantulas' delightful craziness, Waspinator's Butt Monkey-ness...
Transformers Animated deepened this. The Decepticons in this series are in some ways oppressed resistance fighters trying to overthrow a regime that is outdated at best and downright corrupt at worst, but they're less "Rebel Alliance" and more "Al Qaeda". Fans tend to miss this part because Megatron is awesome, Blitzwing is funny, and Starscream is, well, Starscream.
Starscream's usual Draco in Leather Pants treatment is taken Up to Eleven in Prime. Because of his skinny physique and how badly he tends to get punished, fans are quick to paint him as a Jerkass Woobie and some even write Hurt Comfort Fics that ship him with his Arch-EnemyArcee, glossing over the many dogs he's kicked; said dog-kicking includes killing Cliffjumper and throwing his death in the other Autobots' faces whenever he can, threatening Miko in front of an immobile Bulkhead, and taunting a T-cog-less Bumblebee about his inability to transform while holding said T-cog at gunpoint right in front of him.
One-shot villain Madame Catastrophe from Tuff Puppy is often hit with this trope, usually being brainwashed instead of evil.
In the old Voltron cartoon, many girls adored the self-proclaimed evil Prince Lotor, despite his attempts not only to kidnap Princess Allura, kill the Voltron Force and raze her planet to a pile of ash, but also (and repeatedly) to force her into marriage, brainwash her, or commit various other despicable acts; he has never shown an ounce of remorse for any of this. Many fans will attempt to argue that he was forced to do this by his father, even though he hatched and enjoyed half these plans, and though he continued making them after he usurped his father. Others will say it's all out of love for Allura, even though he was willing to throw her away for another princess that looked just like her.
The Brotherhood of Mutants in X-Men: Evolution. Though they were portrayed somewhat sympathetically, and shown at times to be manipulated, they still were jerks that often caused lots of trouble. Their numerous fans usually defend anything Avalanche, Quicksilver, and Toad do and consider the X-Men to be the real villains.
The most extreme example is Quicksilver. While Avalanche and Toad showed that they had some good in them, Quicksilver was a borderline sociopath who had little concern for anyone but himself.
Probably not helped by the fact that in the comics Quicksilver's the one with the more permanent Heel-Face Turn out of all of them, even being a long-standing member of the Avengers.