Swing It Low has Harley Quinn overhearing a conversation between two men that implied the murder of a prostitute. Despite the many terrible things that Harley had been party to, she had never killed a working girl, and found such a crime to be reprehensible. As she thought to herself, they dealt with enough trouble as it was and worked really hard just to eke out a living.
A highly puzzling case in Downfall. The main villain is advocating genocide of the Gotei, instigate a bloody war that claims many lives including named characters and fan favorites. Yet the changes instigated among the Arrancar the policy is 'don't eat wholes - or each other'. Furthermore, their opponents are shown executing enemy wounded at the conclusion of chapter 20. And who is this Big Bad, by the way? Why... Unohana of course!
In Tiberium Wars, the Brotherhood of Nod draws the line at rape, and authorizes summary execution for any soldier caught in the process.
To emphasize this point, at one point a Nod soldier attempts to rape GDI Intelligence officer Sandra Telfair, who has been briefly captured. Before he can start, though, Brother-Captain Allen of the Black Handsmashes down the door, and beats the would-be-rapist's face against a wall before chucking him out a window. The Brotherhood takes this kind of thing seriously.
They go so far as to declare it a sin against Kane.
Colonel Moran makes a very complicated case in Children Of Time. He's more than willing to kill a seventeen-year-old girl — even rape her — but he also respects her unconditional love for Sherlock Holmes and appears to understand it even better than Holmes himself does.
In Cullin' of the Fold, a Redwall fic that's a Mary Sue and Twilight parody, the female protagonist is captured by a quintet of vermin. When two of them begin to poke and prod her, she jumps to the conclusion that they intend to rape her and says so, adding that she won't fight back if they'll just let her go afterwards, leading to this exchange:
Petula: Look ... I have a pretty good idea what you're going to do. I won't fight, if you want. I don't want to make trouble. Just get it over with and let me go.
Raz: Er, Riggy? Tuftail? I fink yer might be givin' 'er the wrong idea.
Riggy and Tuftail: Wot? (they realise what Raz means) EW!
Thunder: Wot's she talkin' about? (Eyeshine whispers an explanation) Yuck! Why'd we wanna do that?
Eyeshine: I have no idea, Thunder old friend. She's heard too many lurid adventuring stories, I suppose. Silly beast. 'Oooh, we're vermin, we're evil! Must go do evil things!' We'd never dream of doing that! It's sick and twisted and disrespectful to femalekind as a whole, and frankly it's disrespectful to us to assume that we'd do such a thing! I apologise if my followers have misled you in such a manner, and I'm sure they do too. Right, buckoes?
Riggy: Yes! I mean no! I mean yes ... No! No, we're not gonna do that! Me sister would kill me!
Raz: Damn right I would, Riggs. We was brung up better'n that! 'Sides, yer don't know where she's been. Yer could catch stuff.
The Fusion FicDeath Note Equestria plays with this. Twilight, as Kira, feels that she's Necessarily Evil and therefore doesn't get to have standards. However, that still doesn't stop her from flipping out whenever someone else crosses the line, and when tying up loose ends after her Memory Gambit, she can't bring herself to kill Apple Bloom (notably the only time she couldn't go through with killing someone).
Byuk is less evil and more of an amoral force of nature, but even he was disgusted when Twilight engineered Rarity and Pinkie's deaths in order to weasel her way onto L's team.
Harry Potter and the Dark Knight even Umbridge (who is part of the reason Harry is on trial in the first place) is unsettled by Harry's raw emotional outburst when he protests his innocence before he is wrongfully thrown into Azkaban.
While Harry isn't evil per se in The Havoc Side of the Force, he does admit to being a mercenary, thief, pirate, murderer, and (depending on your point of view) kidnapper. However, he refuses to tolerate slavery so when he robs a Hutt as part of a job, he makes sure to free every slave and bring them to safety.
Sec: AND THEY DO NOT KNOW THEY SHO-ULD HAVE A-SKED! I HAVE SE-EN THIS WORLD'S EN-TER-TAIN-MENT; I HAVE DONE RE-SEARCH INTO ITS CUL-TURE. YOU HAVE MA-NI-PU-LA-TED ALL FA-CETS OF HU-MANITY TO CON-FORM TO YOUR GO-ALS, TO TAKE YOUR WO-RDS AT FACE VA-LUE! SO YOU MIGHT NE-VER HAVE TO LIE.
Kage: Jade is surprised to find that Raythor, despite being one of Phobos' staunchest and loyalist supporters, still has a code of honer, refusing at first to drag a child (namely her) into their conflict, and being disgusted at how the Guardians and rebels treated her.
My Little Castlevania: As it turns out, while Marble/White Dwarf willingly joined Dracula's minions, she was still moral enough to refuse orders to poison the foals in Ponyville hospital. Of course, this just led to Actrise possessing her to get it done.
In No HoperNeferet is quite angry when she learns that the humans scientists were experimenting on and killing children in their search for a Vampyre cure.
The new Chaos gods from The Open Door have laws, if they can be even called that, so anarchic they would horrify many a self-proclaimed anarchist and their attitude towards combat approaches The Unfettered levels, with brainwashing of POWs being seen as a valid tactic. However, they will not tolerate human trafficking or abuse of children, amongst others. Considering who they used to be, it makes sense. In fact, child murderers get to visit the Hall of Torments after their demise.
Also deconstructed; this partiality towards children doesn't stop them in the least from doing horrible things to anyone who isn't one - or, for that matter, from indoctrinating said children to believe anything they do is just and right. This can come off as quite warped to other races they encounter.
In The Prayer Warriors, when Michael is infiltrating Hogwarts, this trope is lampshaded when Ginny says she doesn't have sex with her brother Ron because, in her words, "Even Satanists have standards." It ends up being subverted when it's later suggested that they had sex. If you consider the Prayer Warriors evil, however, this can be seen as applying to Draco, who wants to kill Dumbledore out of sheer homophobia, getting upset when Michael suggests that Ebony sleep with Harry to get his key.
A Shadow Of The Titans: From Raven's perspective, Jade, who never actively causes trouble, seeks peaceful alternatives, and doesn't take advantage of Raven being unconscious to hurt her, saying it wouldn't be right.
For a straighter example, when Jade and Blackfire face each other in the Tournament of Villainesses, Blackfire is willing to let Jade surrender, as she doesn't want to fight a child. Though when Jade doesn't give up, it doesn't stop her from trying to pummel her.
Also, even the other HIVE villains find the Ax-Crazy Gadjo a bit disturbing.
Even Gadjo has standards, believe it or not, as he thinks fighting is about fighting, not big speeches or special effects, like Susano was doing in the HIVE entrance exam. He also hates zombies and finds the creation of them vile.
The website StarDestroyer.net, concerning the question of whether The Empire from Star Wars would beat The Federation from Star Trek in a war, is written in the character of an Imperial officer. When confronted with Federation transporter technology, he notes that "Although some might claim that life continues if a precise duplicate is created from the original, many feel that the discontinuity of consciousness represents death. This may be regarded as a mere philosophical issue, but our officers and scientists are unanimous in their condemnation of this process as an unconscionable concept", referring to philosophical and moral issues surrounding the technology. This makes sense when you consider the facts: the Federation is a generally atheistic society, while in the Empire you have the very spiritual Jedi and Sith, scientific knowledge of the Force and the proven existence of Force Ghosts.
In Stargate Equestria, when Teal'c and O'Neill question the Jaffa pegasi who ponynapped the Cutie Mark Crusaders, he admits to being ready to interrogate them but is offended at the idea that they'd torture them.
""We would not have hurt them. We will do what we must to serve our goddess, but we are not needlessly cruel."
In Blood Matters Voldemort was upset by Umbridge's detention methods because "he was a bloody Dark Lord and even he wouldn't condone the use of a blood quill on innocent school children."
In The Diadone Method Sirius said "Fuck me now" when he found out that an adopted and name-changed Harry had magic and Harry replied "That's called pedophilia, and kinda looked down upon. Even in the Mafia there are some rules that were not made to be broken."
In the The Dungeon Books Dumbledore, upset that Harry hadn't grown up at the Dursleys', claimed that not living under his mother's protection made him Dark and a potential puppet for Voldemort, then advocated killing a fourteen-year-old. This cased a mass exodus of Order members - including Mundungus Fletcher, because "he may own the loosest morals of the Order, but not even he could condone Harry's murder."
In Heir Voldemort or rather the Horcrux in Harry's scar that gains sentience is sickened by the Dursleys' treatment of Harry. Also Original Character Lethfyren Malfoy, a Mind Healer of shady repute that Voldemort hires (and who Tom calls "a monster") will NOT "do kids." Voldemort himself is strongly against his followers abusing their children though he seemingly has no problems killing them, since he was quite happy to kill at least two children before the events of the story. But then Voldie has a soft spot in his cold black heart for wizarding children-not muggle children.
In Ruby Tinted Glasses it was revealed during Sirius' will reading that Dumbledore had been dipping into the Potter vaults and giving much of it to the Dursleys and Weasleys, prompting Draco Malfoy to comment that "even my family wouldn't stoop so low as to steal money from a child."
In Slytherin Heir Voldemort is outraged upon hearing that Umbridge had such a dark artifact as a blood quill anywhere near the students of Hogwarts let alone was using it on the children for her detentions and his Death Eaters all have similar reactions:
"I have received news that that woman Umbridge is using a Blood Quill in her detentions at Hogwarts." The room exploded into chaos. "What! How dare she!" "A Blood Quill? How many has she used it on?" "She better not have used that on my child! If she has even thought about it, I'll mount her head on my wall." "Is the Minister aware? Did he authorize this?" "Why have we not heard about this until now? She should be in Azkaban for using it even once!" "Forget Azkaban! I say we storm Hogwarts, kill her, and hang her bloody body off the ramparts!" Bellatrix declared with a maniacal laugh.
In The Truth Revealed Lucius Malfoy looks visibly ill when it appears that Voldemort is torturing Harry to death in front of Dumbledore. "Lucius could torture any adult without flinching, but when it came to children... he hated it, as did most of the Death Eaters, especially those with children of their own. Voldemort himself didn't like it, but this case was difference. Very different."
In When the Boat Comes In it was mentioned that due to Lucius Malfoy's standards prohibiting him from killing children and Muggles, Voldemort sent him on assassination missions and nothing else during the first wizarding war.
In both canon and the fanfic Hivefled, the Church of the Mirthful Messiahs is a Religion of Evil in which troll sacrifice is a normal part of worship. In Hivefledverse, the worshippers are by rights supposed to perform the last rites to free the souls of their victims and send them on to be honoured guests of the gods at the Dark Carnival. Many subjugglators don't bother with the rites for those who don't volunteer - "don't want to be clogging up death with a bunch of revered lowbloods" - thus leaving them to wander the crossroads as part of the "hivemind nightmares". The Grand Highblood takes it a step further into horribleness by binding the souls of his victims to himself and using them as puppets to torture his future victims. Gamzee is horrified to find out, and attempts to free them; so far he's only managed to bind them to himself instead, but that's still an improvement.
When Tarakudo is conjured by Uncle and Tohru for interrogation, he compliments Jade's progress, and then offhandedly comments that she'd make a good consort when she's older. When Uncle and Tohru show their disgust over this, he responds that he did say when she was older, saying that he does have standards.
And Viper may be a thief (albeit a reformed one), but she refuses to take part in Jade's plans.
When Jade contorts herself into a snake shape without knowing how to change back, she commands one of the nearby Enforcers to squeeze her until she shifts back to normal. Finn immediately backs away, as he finds the idea of putting his hands on a kid like that just a bit too discomforting, even if she isn't human.
Tarakudo considers it, but simply can't bring himself to simply abandon one of his own kind to torture and death, even though he knows her goal is to overthrow him.
When Hak Foo learned of Valmont's attempt to betray Jade, he mentally and internally reproved the idea because "philosophy of quid pro quo and contracts were the closest thing the mercenary had to honor". Note that, since "his agreement to Chan's girl did not technically cover this", he still decided to take a wait and see policy over that.
When Jade is forced by Ikazuki to attack Uncle's store, even to the point of using the (albeit unspoken) threat of using Molotov Cocktails to burn them out if they try to hide in the warded store (as in, she can't enter) to force them out, she seems to be a little ashamed about it, and she later admits that she wants to prove herself BETTER than the other foes the Chans have faced, NOT more underhanded.
When making a bet with the Enforcers, Jade says that she follows the standards she sets for herself. She does seem to be as big a fan of Exact Words/Loophole Abuse as ever, so when she needs to swallow a sandwich whole for the bet, she simply uses her contortionist abilities to unhinge her jaw, saying that while she promised not to use magic, that wasn't magic.
Later, during Operation Steel Lightning, when Jade gives control of Black's body to General Ozeki, she orders him not to kill anyone when he attacks Section 13 as a diversion for her stealing the masks.
Also, even though Daolon Wong wasn't of any use to her, she didn't kill him (though she did keep him close and locked up, because she's Dangerously Genre Savvy and remembers what happened when Shendu left Daolon Wong be after betraying him).
In Charles Gray's ''fanfic "Buried", someone kidnaps Kim Possible and buries her alive to impress Drakken and hopefully get a job in his organization. Drakken arranges to have the wanna-be henchman killed because he was revolted by what he had done to Kim. In the sequel, "The Chrysanthemum and the Sword" Kim's other villains (except for Monkey Fist) react similarly to her plight (Motor Ed even sends her a get-well card), while Shego works with Barkin and Ron to thwart Monkey Fist's plan to steal some nukes.
When the SUEs are forced to work together in a side story, none of them can stand Hitomi, who enjoys using her Mind Control powers to murder innocent people, or Shizune, a fundamentalist Christian who wants to commit genocide against anyone who doesn't share her religious views.
Nao points out that while she enjoys robbing perverts for fun, she believes murder is something else entirely, hence why she didn't kill any of them. For a similar reason, she rejoins the Himes to deal with Hitomi after she forces a police officer to go on a shooting spree that kills 20 innocent people, and it's implied that the incident reminds her in a sense of the time her father was killed and her mother was put into a coma. She's also reluctant to use lethal force on Shizune unless there's no other option.
The batarian ambassador and assistant to the Manaban Emperor in the Mass Effect fanfic The Council Era (who acknowledges his and his associate's own moral ambiguity) views Tyrin Lieph's attempt at suppressing the manaba through cultural/religious genocide as going too far. The Emperor tortures one of Tyrin's allies to find his location. This results in both the Emperor and the ambassador being victims of Hoist by His Own Petard when Tyrin remotely detonates an electric surge on his ally's body, killing them both.
In the Uplifted series, SS Officer Joachim Hoch has no problem with the idea of deporting all of the Jews from Germany, but draws the line at exterminating them. His adoptive father, SS Officer Gerald Langer seems to feel the same way. Hoch is horrified when he realizes what is happening in the second book. Otto Skorzeny is depicted in a similar fashion, though his ultimate loyalties lie in a different direction than Hoch's.
Hoch later shot one of his own subordinates after said officer killed a British man who was insulting them. He then states that anyone under his command who commits or orders the killing of a civilian will face the same fate.
Earth and Sky has an example played for laughs that crosses over with Pity the Kidnapper. The Changelings kidnap Diamond Tiara in chapter 29, and two chapters later are shown throwing her out of their hive, because even they find her unpleasant.
Getting Back on Your Hooves: The Diamond Dogs are perfectly willing to help Checker Monarch ruin the life of a mare they don't even know as long as they're paid. However, even they're horrified when Checker Mind Rapes Rainbow Dash with nightmares in order to turn her on Trixie. They still work for her after this, but now they're actively terrified of her.
Diamond Tiara may be a bully — and proud of it — but even she is sickened when it becomes publicly known that Checker has been ruining the life of her own sister.
In a Loose Canon side story of the Pony POV Series Canon!Discord was horrified at the atrocities his Pony POV counterpart did in the Bad Future despite having the same personality and sense of humor. So much, that Canon!Discord pulled a Heel-Face Turn.
I think it had a lot to do with getting an outside view of his actions, causing him to have a Heel Realization.
In the Xenophilia-verse, Honeybee, like her sisters, is first introduced as an intolerant bitch who is disgusted by Rainbow Dash, Twilight and Lyra's relationship with Lero, a human. But while she finds interspecies mating perverted, she reveals that she doesn't dislike Lero himself and she refuses to continue harassing them after he saves her from drowning in "Fish Out of Water."
In Return to the Swarm, turning ponies into "synthetic changelings" is considered vile by changeling standards, an expressly forbidden. Also, by the end of the fic, the standard routine of capturing ponies and stealing their identities is outlawed after Crysalis ends up the victim of the same thing. (Fortunately the protagonists have discovered a much more acceptable way of love-feeding: friendship.)
Within the warped and inconsistent moral code outlined in Naruto Veangance Revelaitons, Naruto's reluctance to have sex with Sakura out of a desire to not hurt her boyfriend Ronan can be seen as this, even if he ultimately gives in. Also there's Ronan, who is disgusted by men having sex with each other is outraged to learn that one of the Council's plans is to kill all gay people, declaring that in spite of not liking gay men, he would never kill them. Proof that he's tolerant, as befits this trope.
Reactions uses this trope liberally. Even Orochimaru, Zabuza, Danzo, and Madara think Kakashi/Naruto is sick. Reasoning varies from the fact Kakashi is a grown man and Naruto is a child, to worry about the psychological trauma to the resident jinchuuriki, to believing it a violation of the trust between teacher and student.
Dragon Master has Giovanni of Team Rocket delivering the line to power-mad Claire and refusing to continue their alliance. In another scene, Laine confronts Ember about the circumstances of her father's death, and he reassures her that it would have to have been an accident because even Team Rocket has standards. Also Team Rocket is treated as a necessary evil by the Pokemon League for this reason.
War Games features Rubeus, after resurrecting the Dark Kingdom, attempting to kill Chibiusa for foiling his plans in the prelude to the story. However, the resurrected Beryl does not approve of harming children and scolds Rubeus for trying to during his first act for the Dark Kingdom. This actually leads Beryl to do a Heel-Face Turn once she realizes that Queen Metaria has given Rubeus free reign, and she regains her memory of an elementary school being blown up by terrorists during her time as queen of what was once the North Pole Kingdom, becoming good friends with the Sailors and eventually earning their trust
In Ultimate Spider-Woman: Change With The Light, the supervillain Blizzard turns out to be much more of a petty thug than a sadist or murderer, unlike most of Spider-Woman's enemies. Although Spider-Woman defeats him when he tries to rob an armored car, he doesn't hold a grudge against her and later helps her protect many of New York's civilians when the city is invaded by an army of Brainwashed and Crazy supervillains. He also disdains the rest of Spider-Woman's Rogues Gallery for their sadism and cruelty, providing helpful advice to Tarot when he finds that she doesn't care about revenge on Spider-Woman either and isn't a monster either. Also, although NYPD Detective Jason Phillip Macendale is a very Dirty Cop, freely accepting bribes from the Kingpin's syndicate, when Kitty Pryde is threatened by anti-mutant racists, he does his job as a police officer and investigates the crime wholeheartedly. Detective Macendale is royally pissed off by the way that the anti-mutant activists justify their actions with motherhood-and-apple-pie statements like saying that they're protecting the community or their families, since in his mind they're no better than him and at least he admits that he's a corrupt son of a bitch.
Played with in a Knights of the Old RepublicFan Fiction in which The Mind Wipe doesn't take effect for more than two days. Revan in disgust says that he has never raped, or condoned rape. Then he thinks, is violating a person's mind, soul, and spirit really any different? However due to that thought he follows the official end and converts back to the light side, of course while still being as close to being a Anti-Hero as he can while being light.
Jewel Of Darkness: When Slade first comes across the young Raven, she's about to be raped by a homeless drunk, and Slade decides to kill him, as even he finds that disgusting. Not that it matters, since Raven's powers instinctively protect her and kill the man, but it's the thought that counts.
Yuuka Kazami in Imperfect Metamorphosis has a surprisingly rigid set of standards for an Eldritch Abomination; the problem is that they make no sense to anyone except her. She views courtesy and decorum as of the utmost importance (to the point that she killed the previous owners of her Inn room because they decided to scream in terror instead of greeting her politely), anyone killing plants puts her swiftly into This Is Unforgivable territory, and while she is glad to protect children from harm she apparently doesn't consider raping them to be harmful.
In Return to Prince Manor Maeve, Queen of the Winter Court was upset with one of her sons because:
I never kidnapped a Seelie royal daughter and subjugated her with a collar, nor did I presume to steal away two young scions of the Prince line and attempt to convert them to darkness. I played my games with mere mortal riffraff, never my own kind . . . unless they were my subjects and due chastisement.