Optimus Prime has a very clear opinion on this, with his famous "Freedom is the right of all sentient beings" motto. The series, though, have sometimes defined sentience in an unsatisfying way - not having a spark renders you a 'drone' even if said 'drone' clearly thinks and feels. In a non-canon series of Transformers Animated comics (with a few Out of Character moments, though mostly confined to Megatron being generically evil instead of a Magnificent Bastard) Bumblebee is told by Optimus not to mourn for Afterburn because he was a sparkless drone, and it's not clear who is right (Afterburn appears to think and feel, and Bumblebee cared about him and it sure seems a Jerkass move to callously tell him that the friend he just saw torn in half was just a drone and thus not worth any worry, but he was a Decepticon infiltrator, only pretending to be friends with Bee or anybody, was killed by Megatron in a You Have Failed Me moment, and could well have been acting according to the "make nice with the mark" programming you'd expect an advanced but nonsentient infiltration-bot to have. And since whether he was real or not, any friendship he had with the Autobots clearly wasn't, he kinda isn't worth crying over either way. Still, be nice to poor Bee, huh?)
In the original The Transformers, Optimus Prime uses a device called "Dominator Disks" to force the Constructicons to help him against their will. As T Fwiki stats:
T Fwiki:Prime sure goes along with the notion of enslaving one of his enemies pretty readily, huh? What happened to his ol' "Freedom is the Right of All Sentient Beings" schtick?
Human characters who don't regard Cybertronians as sentient beings are, in general, not treated sympathetically by any series in the franchise. However, it's apparently okay for younger viewers to see a Transformer die, even in a time slot where killing off a human character would bring down the wrath of the Media Watchdogs upon all involved. This may be more of a method of Getting Crap Past the Radar.
The Dinobots in Animated. After the incident that gives them the ability to function on their own, Prowl is the only one to suspect that they're truly alive. They are huge, lumbering, and destructive, and Prowl is shocked when, after their defeat, Optimus Prime agrees with the decision to melt them down. So he and Bulkhead sneak out in the middle of the night and transport the Dinobots to a forested island where, concealed by holograms, they can live peacefully. Later, Porter C. Powell argued that since Transformers have no legal status, it's not a crime to do anything to them. (He's a Jerkass, and we're not meant to agree with him.) Later, they use their lack of legal status to threaten (and eat) him with impunity. (Don't worry, Grimlock spits him back out unharmed; these are the Autobots we're talking about.)
It has more to do with the fact that Grimlock has good taste, and with all the hair product necessary to keep his rockin' mullet in place, Porter C. Powell probably tastes horrible.
Darkheart is a demon and the Big Bad in Care Bears Movie II: A New Generation. From scene one, there's absolutely no doubt that he is profoundly evil, as he tries to kill off all the Care Bears when they are babies. During the course of the movie, not only has he added further attempts to kill the Bears to his evil resume, he has also turned a campground full of children into a den of evil and bound the little girl Christie to a Faustian bargain; he'll make her a Born Winner if she aids him in his evil plans. About halfway through the film, Darkheart joins Christie in a rowboat shortly after capturing a significant number of the good characters with her help. Darkheart falls out of the boat and Christie rescues him, leading to the quote above. The incident messes with Darkheart's head as well, and later on, when he hurts Christie, he vows to be a good guy (probably the fastest Heel–Face Turn ever) if the Bears will save her.
The Care Bears Family series had a Big Bad named No-Heart (creative writers, these) who was darn near identical to Darkheart. The thing is, nobody questioned whether or not he had a good side. Well, he was named No-Heart.
In Samurai Jack, expendable robots have variable intelligence, so despite Jack meeting all kinds of bizarre races the audience doesn't feel bad for them. A significant portion of the enemies faced by Jack appear to be completely organic, sometimes more so than actual organic beings, and only prove to be robotic when sliced open.
A strange and very bleak exception is one late Film Noir episode featuring a troubled but sympathetic robot-turned-hitman who conveniently gets an Emotion Chip, building up to the inevitable but stark ending where he fails and gets dispatched by Jack - who isn't even aware of it.
There's a fantastic moment at the end of the episode when, with his last breath, X9 asks Jack to take care of his dog. Jack looks back over his shoulder and a brief look of doubt crosses his face.
There was also an episode where two young siblings and their charming robot servant are brought to Aku. When the demon orders the kids around and their robot protests, he casually destroys the robot and the deed is treated by the kids with as much horror as any coldblooded murder.
This strange double standard results from the arbitrary censorship rules that the cartoon makers had to work within. It's okay to show suffering and death, even of sentient beings, so long as nothing actually bleeds. Thus, anything that has to be dispatched handily will ultimately prove to be robotic or otherwise nonliving. The point is clearly made in the pilot, where Jack shows his baddassery by cutting off a mercenary's hands, which, naturally, were bionic. Later in the same pilot, he destroys an army of gigantic robotic scarabs. Each bug he slices open sprays a wealth of black oil everywhere, culminating in a scene that is extremely brutal and gory while, technically, no living things are hurt. Moreover, the last robot "alive" bails and tries to run away. Jack just says "No... no escape" and finishes it off, and no further consideration is given to the moral equivalence of murdering a surrendered and retreating enemy in cold blood.
When Jack does fight organic creatures, such as a group of bounty hunters that were definitely not robots, they are generally killed by a bloodless slash from his sword or their fate is obscured by an explosion. The one time humans are killed is in a flashback that serves as a reference to Lone Wolf and Cub, and the assailants that are cut down are dispatched just off screen.
Jack has never turned down anyone in need due to species. Human, Robot, Ape, Alien, Talking Dog, no matter. The only thing important was that someone needed his protection. He's reacted with horror at seeing a village of robots destroyed just as much as one of organic creatures.
Still, the extent of carnage and violence in which Tartakovsky indulged under sole excuse of this trope is unsettling. It's not just that robots can be killed on-screen - they can be killed in horrifying ways on screen. They are burned, dissolved in acid, disemboweled in slow-mo, cannibalised and devoured alive by a huge monster. At this they sometimes clearly express emotions, namely pain and horror, and other times they look exactly like living beings right until the moment of death.
In the penultimate episode of Danny Phantom, this issue became a plot point in more ways than one since the subject in question is both a Half-Human Hybridand a clone:
Danny: She's not just a ghost, she's also a girl. And if Vlad destroys the ghost half, the human half is destroyed along with it. Valerie: No, that's not my problem. She is a ghost, and I destroy ghosts! Danny: Fine! Destroy ghosts! But can you really take part in destroying a human?
Also called up in Danielle's premiere episode- Vlad became fully irredeemable when he treated her as less than human in the climax-
Also played straight in the same episode when both Danny and Danielle had no qualms seeing the perfect clone die in their hands. Considering said clone is a step above Danielle and clearly shows conscience as he dies, this is a rather jarring matter.
Megas XLR will never kill off humans, and will only very rarely have any kind of organic being die. The giant robots that are frequently the enemies though, are cannon fodder, regardless of their level of sentience. One particularly extreme example is when Coop accidentally blows up a planet of sentient robots (although they wereAx-Crazy and sort of fascist). If they could get away with it, the writers would also have plenty of humans killed to (and a few still are).
Ben 10 starts playing "the hypocrite type" about this at the beginning of the series and later really straight in its sequels. In the earlier episodes of original series,you can accurately predict how much violence is inflicted on an enemy based on how humanlike they are. Actual humans are merely subdued, but non-complex life forms and Vilgax's "sentient robots" are often exploded on screen, though not graphically detailed. This becomes especially awkward when you realize that, thanks to the very nature of the powers of the Omnitrix, Ben himself isn't human half the time!
Almost reverted back to "hypocrite mode" when in an episode where an alien bride at a marriage between a pair of Star-Crossed Lovers has to help Ben kill her parents so she can marry her human groom. She makes a disturbingly nonchalant joke right afterwards. As if to bring the thing home, she assumes a form that looks far more humanoid than the evil members of her family. But it's later mentioned that her race are incredibly tough and difficult to kill with the implication that the parents will be fine until the ceremony is over.
In Alien Force, the first sequel, the Plumbers are revealed to be an intergalactic peace-keeping force, with both human and alien members, that also show to maintain stronger bonds, to the point of making hybrids.
In the same sequel, a pair of alien-human hybrids starts capturing many species of aliens and sending them into the Null Void, thinking that all aliens on Earth are evil (which is ironic due to the fact that they also aren't full human). Though part of those who were captured were really criminals, the majority were probably hybrids just like them. The episode ends with the duo going to the Null Void to rescue those they wrongfully imprisoned.
Continuing the trend, Gwen scolds Kevin that "You hit him too hard!" when he decks a guard. Kevin placates her with, "Not him. It." and removes the holographic mask disguising the parasite alien as a human. This could be potentially problematic, as a later episode reveals that these aliens are in fact humans taken over by alien parasites, and the Omnitrix is capable of reversing the transformation. In the Season Finale, Ben states that they never actually kill any of them for that reason, and he then starts using the Omnitrix to cure them on a large scale though only in the season finale as he didn't the Master Control unlocked, letting him do whatever the fuck he wanted with the Omnitrix. He was limited to skin contact before that.
In Ben 10: Ultimate Alien, Ben's Berserk Button is activated at full force when Agreggor kills a group of aliens in front of him, to the point of needing his cousin's powers to chill him down. So it's safe to assume that only bad aliens deserve a beatdown from his part.
A tip of the hat to The Brave Little Toaster, the movie that made some of us feel just a little guilty about replacing old household machines with new ones.
To be fair, the people in the movies are unaware of the appliances being alive. Thomas the Tank Engine, on the other hand...(see below).
Populated, as it is, by humans, robots, sewer mutants, talking animals, and aliens of all varieties, Futurama naturally takes this one on with tongue firmly in cheek. To wit:
Fry: So we're going to an uninhabited planet? Bender: No, it's inhabited by robots! Fry: Oh... you mean like a garage is inhabited by boxes.
Furthermore (and possibly as a tribute to The Brave Little Toaster) Professor Farnsworth "teaches the toaster how to love". In a dream sequence he goes so far as to bring it to life, turning it into a raccoon. Everyone else still treats it like an old toaster... might have something to do with the two slots and heating coils that are still in its back.
Robots in this setting don't seem to have any legal rights. They are not actively sought out and destroyed, but older, malfunctioning robots are melted down, seemingly without their consent, and they are still treated as property. Bender usually gets a free pass, though — the main cast, at least, seems to see him as a person.
As far as robots go, this trope seems to be Zig-Zagged based on the Rule of Funny. In a different episode, robots are shown to be able to vote in elections — and in fact, because they vastly outnumber humans, the robot vote turns out to be the sole deciding factor in choosing the next President of Earth. Richard Nixon (It Makes Sense in Context) ends up winning without getting a single human vote, merely by being popular with the robots, and he remains the President for the rest of the series after that point.
In many episodes, the robots are shown essentially having an entirely separate society from the humans, with their own popular media ("All My Circuits", the robot soap opera with a Token Human character), religion, and even organized crime (the Robot Mafia). The extent to which this society interacts with humans varies from episode to episode; sometimes there's no interaction at all; sometimes big wheels in the robot society are treated with importance by humans as well (and rich robots may even be shown having human servants); sometimes, robots are just walking scrap metal.
Mix Carnivore Confusion into the issue, and you've got yourself The Problem With Popplers episode.
However, all this may be Life Is Cheap played for laughs. Respect for sentient life in general is pretty poor. In fact, aliens come to Earth to steal noses as an aphrodisiac and nobody really cares, Earth is invaded multiple times over fairly trivial things with zero political fallout, and suicide booths are on almost every corner.
Remy the rat has to fight hard for respect in Ratatouille.
WALL•E. The inhabitants of the Axiom generally treat the robots as cruise crew (which is understandable given that they're on a cruise) or as video game characters (which... is a product of lazy ignorance more then anything). This is probably a general BnL stance; convenience before ethics. However, McCrea gets a major wake-up call in the form of the A113 recording, and from that point on treats robots as people. It's shown at the end that ALL the humans are genuinely shocked and dismayed at WALL•E's mangled form, so...
Continuation fan fics generally have a lot of deep probing questions about this trope; whether a robot is considered criminal, defective, or insane, how robot marriages would work, the exact question of robot children, should robots and humans even live together...
In the W.I.T.C.H. episode "H is for Hunted", Will is brought to tears after unknowingly trying to absorb an Astral Drop (normally soulless) that Nerissa has transformed into a living, feeling Altamere.
The Venture Bros.: Brock Sampson has a code against killing women and children. He was curious if there were any circumstances in which that would be dismissed. Eventually, his mentor accepted "Lady Dracula", as undead don't count.
And in the two-part Season 3 finale, "The Family That Slays Together, Stays Together" (Part 1, to be specific), once The Monarch has infiltrated the Venture Compound, he reviews the plan with his team. Number 24's part is to "Subdue the Venture robot" to which Monarch replies, "Subdue? You can kill the robot, it's a robot."
Though in part 2, it's revealed The Guild of Calamitous Intent of all people forbids harsh torture of anything, even robots, so long as they are sentient. Assuming that part was true and not just part of Dr. Mrs. The Monarch's Good Cop/Bad Cop scheme.
Dr. Mrs. The Monarch: Monarch, this goes against The Guild's sentience conference of 1998!
Buzz Lightyear of Star Command has hordes of robot drones that are just there to be shot (granted, they don't appear to possess any brain function). More egregious examples are NOS-4-A2 (a robot that is, to all outward appearances, sentient and the only non-drone villain to be actually killed) and XR, the Plucky Comic ReliefRobot Buddy who spends much of his time getting blown up, crushed, dismembered and tortured in various ways- and none of the protagonists seem to care, despite the fact XR displays myriad human traits and emotions (having outbursts rivaling those of a hormonal 13-year-old girl) and has just as well-rounded a personality as any organic character on the show. As a result, a far amount of Fan Fic looks at him as a victim. It may just be because XR gets better every time. Still, he seems to feel pain, and react to it accordingly.
In the original movie pilot for the series, XR debuts as a non-sentient robotic mission partner to Buzz. On his first mission, he is brutally destroyed by Buzz's nemesis, Agent Z. Interestingly, Buzz is notably distraught at XR's "death" and later urges the LGMs to fix him, whose scatterbrained attempts to do so result in the sentient and quirky XR later seen.
The way this applies to giant monsters is partially subverted in Invader Zim, when Zim transforms a hamster into a giant monster. Even though it's on a rampage, people still stop to gawk at how cute it is.
SpongeBob: All we have left is this apple! [a worm emerges from it] Worm: Hello, sea creatures! I bring you greetings from Apple World! [the scallop approves and jumps up for it] SpongeBob: Of course! Scallops love worms! [picks up the worms] Worm: Huh, wait! We will bury yooooou! [drops it into the scallop's mouth and the scallop eats it]
The original Teenage Mutant Ninja Turtles animated series gave the Turtles a chance to actually use their weapons as forces of deadliness by turning Shredder's foot soldiers into robots.
Possibly the most WTF example of this is the episode "Donatello's Duplicate", where Donatello creates a clone of himself specifically to have it do his chores for him, and treats the duplicate as his slave. When the clone turns against him and becomes evil, it gets wiped out of existence. And it's apparently perfectly okay by all the others. You know, the good guys.
And there's also Metalhead, the robotic Ninja Turtle, who has no rights. For this to be more acceptable, it has a tendency to go berserk (or switch sides), thereby destroying the illusion that it has real sentience or "free will".
Teenage Mutant Ninja Turtles (2012): After Snake's mutation into Snakeweed, the Turtles has no qualms against potentially lethally electrocuting him. Of course, since he was working with the Kraang and helped them capture April and her father beforehand, they weren't very concerned with his safety when he was still human, either.
Anything by Don Bluth. Generally, the less human a character looks, the cartoonier their animation, the less respect they receive from the story. Non-human minor characters (unless they are effectively human due to Rotoscoping) are prone to be splatted at any moment, without a death scene to drum up audience sympathy.
In the Disney Fluppy DogsPilot Movie, Stanley, who is a humanoid dog-like alien posing as a dog, is about to turn in for the night. His human friend, Jaimie, is asked by Stanley where he is going to sleep and the boy is about to tell him to sleep on the floor like an animal. Fortunately, Jaimie realizes just in time that he was about to humiliate his intelligent friend and invites Stanley to sleep in his bed with him.
Aladdin: The Series, in the episode "Garden of Evil" with the villain Arbutus. He is a plant like creature that makes art by controlling and growing plants, and who voices his dislike of humans for destroying them. In the end Aladdin killing Arbutus is played as a mistake and the flower cut from his body (which kills him) is replanted in the ground.
Despite being completely sentient and regularly conversing with their humans, the trains in Thomas the Tank Engine are thrown out in the scrap pile and essentially killed when they stop being useful. Some of the books and episodes even hint that managers of certain railways wouldn't blink an eye at scrapping an engine with lots of life left in it, if it helped their bottom line. Cue lots of terror. Couldn't they make some kind of retirement home or something?
In one book, a real engine comes from a heritage line in South East England to visit (the book was especially written to promote the line) and in another Thomas visits the National Railway Museum in York. Those could count as retirement homes.
It gets even worse with this series when one realizes that, canonically, the show is set in the 1950s and real-life railways in Britain started to scrap all their steam engines in the 1960s.
In Kong: The Animated Series, the only characters to possibly die are Set, Onimous, Harpy, and Chiros - all of whom are evil monsters. Ramone De La Porta is just as evil and power-hungry as any of them, yet he is not killed (though suffers a Fate Worse Than Death brought on by Chiros). Main characters attempt to save him whenever he is in mortal danger, even though they know how evil he is, and it would save them a lot of trouble and having to foil his evil plans if they just let him die one of these times. The same goes for Andre, the arms dealer, in one of his two major appearances.
It could be argued that Onimous survived his sinking into quicksand (but remained trapped there), Harpy (who was struck by a lightning bolt) was merely turned to stone through magic rather than death (and could be changed back with some magic spell), and Chiros's stone being destroyed (after he was imprisoned inside it) did not kill him but prevented him from ever being awakened again. As this is the last we ever see of them, there is no way to tell.
In Phineas and Ferb, Night of the Living Gelatin, while the monster is dying it calls out to it's master. And Doofenshmirtz is upset at it dying and in fact chases after Perry when he is leaving.
In "Where's Perry Part 2", Perry, Major Monogram, and Candace are taking out an army of robot doubles of the main cast. None of the robots show any remorse for their actions, with the exception of Robot!Candace, who sacrifices itself to save Candace after seeing her room and listening to a message from Jeremy. Her explanation for the sacrifice is pretty tear-jerking as well.
Robot!Candace: No Jeremy robot for me...
Star Wars: The Clone Wars has the same problems with battledroids and sometimes Clone Troopers as shown in the films, but the show went to absurd lengths with the Geonosians from Attack of the Clones. Like in the film they get casually sliced in halves by Jedi and Clones even use Flamethrowers to set them on fire with them even screaming and running away, all of it ON SCREEN. It is never explained why they get such brutal treatment in comparison to just about every other species. You see Jedi cutting off the heads and arms of clone troopers in Revenge of the Sith, but nowhere they explain why they have to slice Geonosians whole body VERTICALLY.
At least they got zombiefied in the last two episodes of the Geonosis arc, but it still is no excuse for before.
While ReBoottries to treat the Bi-Nomes like actual people, the show falls victim to this trope. Someone needs to die? Bi-Nome. Need victims for a lost game? Bi-Nomes. Need someone to play Red Shirt against Megabyte? Bi-Nome.
Humorously enough, one episode had Matrix ruthlessly destroy a bunch of robot drones after confirming that they didn't have personality chips. Later on in the episode, AndrAia asks if another Guardian's drone had a personality chip, and the robot runs off terrified.
Played sadly straight in My Life as a Teenage Robot. Although no one, not even her creator, questions the fact that Jenny is a sentient robot teenager deserving of love and respect, most episodes have her killing or pummeling non human looking robots such as the villain robot's insect-like minions. Note that the main villain herself looks like a very alluring, feminine robot who's usually allowed to get away from harm with hardly a life-threatening scratch. The fact that Jenny usually has her own body blown to smithereens is played for laughs.
When Buster from Arthur fantasizes about himself as a superhero named Cat Saver, he encounters a villain with some... unconventionalmooks. He prefaces his fight with a disclaimer to the audience: "Kids, hitting and punching people is wrong." But that's no person! It's a giant ham!"
In an episode of Young Justice, Miss Martian "killed" the robotic mannequin controlling Mr. Twister. The others complain about her smashing a guy, but once they find out he's a robot, they let the matter drop. It was ironic since one of their mentors Red Tornado is a robot and played a prominent role in the episode. It wasn't sapient like Red Tornado but Miss Martian didn't know that and she just assumed that it wasn't.
In the second episode of Avengers Assemble, the Avengers indiscriminately kill the attacking Space Phantoms, despite the creatures displaying sentience and the ability to speak. They do the same thing to an army of vampires in a later episode. It is however worth noting that the show is heavily inspired by the Marvel Cinematic Universe, where the heroes generally have noqualms with killing their enemies.
Played with in Family Guy. Brian, along with a few other dogs in the series, is sentient, walks, talks, drives, and has romantic relationships with other humans. Despite this, he's still treated like a regular dog. This is referenced in a few episodes, one where he gets in a legal battle to avoid being euthanized and to have the same rights as a human, and another where he accidentally hits a dog with his car and grows upset when he learns it isn't a crime to kill a dog.
There was also another episode where a talking, sentient cow is about to be slaughtered for meat, but Brian and Peter break him out. As with Brian, it hits this trope because overall, the cow does behave like a human but is still treated like an animal. Said cow does end up winning a lawsuit against the fast food company that was going to kill him and the other cows.
In one cutaway gag, Mayor McCheese gets shot instead of John F. Kennedy, with his head bursting up and Jackie Kennedy starting to eat it. Which leads Stewie and Brian to lampshade this:
Brian:"That joke's not in bad taste, right?"
Stewie:"Who cares? He's a cheeseburger."
When one thinks about Foster's Home for Imaginary Friendstoo hard, they'll notice that imaginaries are essentially treated as sapient pets. They are given to wanting adopters whether the results are positive or otherwise and children can get rid of them when they grow up yet they can carry jobs (though some episodes show the idea of an imaginary as cheap labour is morally wrong) and mingle amongst humans easily. It seems to be though that the imaginary friends enjoy (or at least are never bothered by it) their life as companions to be constantly used and thrown away.
The Batman vs. Dracula: While Batman plans from the start to synthesize a cure for Dracula's human victims, he has no qualms against simply killing Dracula, blatantly telling Alfred that "Dracula's not a man, he's a monster." Of course, he does at least try to use the vampire cure on Dracula beforehand.
Teen Titans seems to follow these general guidelines: robots and monsters can be massacred by the dozens - or indeed, by the planet-fulls - so long as they don't have any dialogue; sentient beings who are blatantly non-human can be killed, but the heroes can't (intentionally) be the ones to do it; meanwhile, human beings never die (with the notable exception of Slade).
While all forms of killing are okay in a Celebrity Deathmatch, but if a non-human or "abnormal" human fights a normal human who isn't a main character, the non-human will generally win. At least one fight inverts the One-Winged Angel trend: Frankenstein's Monster and the Wolfman are unable to hit each other while they're both monsters, but when the Wolfman transforms into a human, Frankenstein's Monster easily knocks the Wolfman's head off.
Discussed and averted in The Avengers: United They Stand episode "Remnants." The Avengers consider killing the robots they discover on the island, but aren't sure if the robots matter morally or not and decide to avoid killing them until they can be sure. Eventually they discover that the robots will kill everyone else on Earth and have the UN nuke the island. They deeply regret the robots' deaths and feel just as bad as if they had been forced to kill humans.
In Batman: The Animated Series, Poison Ivy's plant-based artificial humans are fair game to be killed and, especially in "Chemistry", tend to die in particularly gruesome ways for a kid's show. One notable subversion is Batman's robotic copy from "His Silicon Soul", where after it is "killed" Batman actually expresses regret and wonders if it's possible that the thing had a soul.
In The Spectacular Spiderman after Peter frees himself from the Symbiont, the first he does is try to destroy it. Sure, the Symbiont attempted to take control over him, turned him into a jerk and nearly pushed him to killing Dr. Octopus, but then many, if not all, of his human or meta-human enemies have repeatedly tried to murder him, endangered other people and comitted all kinds of crimes, and yet he never entertained the idea of killing any of them. But with the Symbiont he decides that "it's too dangerous, it could fall into the wrong hands" and BAM, it's deep freeze time, nevermind that "it" is also a sentient being!
Steven Universe plays around with this trope in the form of why the Crystal Gems are on Earth. Initially it seems like they are there to just protect humanity and they fight a series of nightmarish monsters to ensure that they don't harm people. However, as the series progresses, it becomes far more apparent that the Crystal Gems are more indebted and in-service to the planet and not just humanity (as they consider all the life on Earth sacred), and the reveal that the monsters they've been fighting are corrupted forms of their own species that they have no method to heal blurs the line on just how "human" their adversaries are. Later gets Zig Zagged when Homeworld Gems start showing up as adversaries, who are treated with just as much hostility as the monstrous enemies despite being humanoid.
Peridot tries to use this argument in the episode "It Could've Been Great" when describing how Rose Quartz's rebellion against the Homeworld prevented the development of the Earth Gem Colony and sacrificed the lives of potentially hundreds of thousands or millions of Gems that could've been made there. What Perdiot forgot to account for was the the Earth already harbored life, so its development as a colony would've killed everything on the planet for the sake of their species, essentially throwing her own argument back at her.
In Superman/Batman: Apocalypse, Superman is forced to vaporize an entire army of Doomsdays to save the rest of Amazons. He drops to his knees in exhaustion and is remorseful that he killed living creatures, even if they were Doomsday clones. Wonder Woman ends up telling him that they weren't really living as they didn't really bleed.
Subverted in Teen Titans Go!. Cyborg is perfectly fine with being a cyborg. This trope gets parodied in "Let's Get Serious". When complaining that the others are too goofy and one-dimensional, Robin points out that Cyborg "should" feel conflicted on whether he is human or not. After everyone becomes serious, Cyborg spends the rest of the episode feeling angsty about his existence.
Comes up at times with regard to robots in Phantom 2040. Heisenberg, the first robot to clearly gain sentience, goes on a long personal journey to figure out his place in the world. Later on, he defends Pavlova from being reprogrammed, stating outright that if she can express the desire to maintain her own mind, she is at least philosophically human. Pavlova herself subsequently argues against deleting Mister Cairo's personality, since even if his intelligence is artificial, it would still be murder. Heisenberg later starts spreading self-awareness to other robots.
In G.I. Joe: Every human character, good or bad, is shown jumping, swimming or parachuting from his or her vehicle just before it explodes. Robot soldiers, on the other hand, are destroyed regularly.
The gargoyles in the series Gargoyles are also held by many humans for monsters, although there were in the entire series just two nasty gargoyles, but many evil humans.