Aversion: In It's Walky!, when Joyce kills her Evil Twin (who has only existed for hours), her friends in SEMME are forced to eventually arrest her for murder. She eventually gets off of it, but not because of the value of the clone's life.
Turned upside-down in this page from I Was Kidnapped by Lesbian Pirates from Outer Space; the pirates fatally shoot what the narration assures us is "really an unfeeling, heartless android. It's OK to kill him!" But in the last panel, it shows an alien woman sobbing over the dead android.
Hey, that's an expensive piece of equipment! If someone shot a hole through my Unimog I'd probably cry too!
The Order of the Stick prequel book, "Start of Darkness" reveals that the gods really did create humanoid races such as goblins and kobolds purely as a source of XP for the 'proper' races. Understandably, they're pretty pissed about this, and the antagonist Redcloak's plan involves holding the gods to ransom to try and get a better deal for all 'savage' races.
Another Redcloak example: Redcloak is a goblin, eventually leading a hobgoblin army (the "hob" bit makes a big difference when you're a (hob/)goblin), and he's willing (and eager) to throw away their lives since they're just hobgoblins. Then one of them sacrifices himself to save Redcloak, and he realizes the insanity of throwing away their lives, since they're goblins just like him. (So not "What measure is a non human?", but "What measure is a hob goblin?")
In a later comic we have Celia calling Haley out for using this trope. After Belkar kills one of the hobgoblins in the group keeping them from leaving Azure City, Haley rationalizes the act, saying that it's one less Hobgoblin for The Resistance to fight. Then Belkar knifes a random benign gnome and Haley freaks out, prompting Celia's response.
Celia: "Wait, Haley! I have a solution. We paint the corpse orange and sharpen his teeth a little. You know, so you can rationalize it more easily."
They (The hobgoblins) were part of the invading army, and in uniform!
That one was a bit of a subversion, since one of the human rebels notes "I don't think we need to bother Thahn with the particulars of this..."
We also have the character of Miko. As a stereotypical "detect first, smite second, ask questions never" Paladin, she makes it quite clear that the value of an Evil creature is zero. Even if it is human. Even then her opinion of Evil by the end becomes "Anyone who doesn't agree with her".
The usage of this trope and the effects such a mindset has is a constant theme in the comic. In one storyline, the mother of the black dragon the Order killed in the starmetal arc wants revenge on Vaarsuvius for her son's death. It's revealed she lost his father in the same manner—killed by adventurers for treasure and XP.
And then Vaarsuvius uses an attack called "Familicide". Yeah.
And the implications of that one are examined very thoroughly.
Tsukiko, a mystic theurge who joins Team Evil, believes and treats undead like people, and, ahem, loves them. She even calls them her "children." Redcloak, however, points out that the undead are just "weapons" made of bones and flesh and dark energy. He proves his point by seizing control over Tsukiko's "children" with Command Undead, ordering them to restrain and drain her life, eat her corpse, and then destroy themselves. They happily comply, leading to some pretty nightmare-inducing lines from Tsukiko. However, there are many kinds of undead in the setting, some sapient like Xykon and some just the magic equivalent of machines, but as far as Redcloak is concerned the only difference is the methods needed to control them.
Half this, half Carnivore Confusion. There is a debate in the world of Furrae whether "Creatures" (supernaturals like Succubi) should eat "Beings" (sentient anthropomorphic animals), and whether or not it's any worse than Beings eating livestock. Many Creatures argue that it's a law of nature that the stronger eat the weaker, whilst Beings insist that you're not supposed to eat sentient entities.
DMFA also has one of the few examples of killing the undead being depicted as reprehensible. Undead fully retain their memories and personality when they rise, so they're still the same person as they were before they died. Unfortunately, many of the living are less than welcoming when their former friends and relatives return from the grave.
Completely averted in A Miracle of Science. Artificial Intelligences are considered people, both legally and ethically. Especially notable since the Evil Plan of the Mad Scientist they're hunting is to Take Over the World using a robot army. Even though he's a villain and thus exempt from the moral standards held by the protagonists and society in large, he still treats his creations with respect and actually listens to their advice]
Further respect for the AIs: Benjamin and Caprice are getting shot at by an army of robots. They grab a motorcycle and run for it, until Mars can determine that their pursuers are simple robots, not Artificial Intelligences, at which point Benjamin makes quick work of them with his pistol rail gun.
Most of this is the result of the amorality/madness of typical sparks. After all, they're just as happy to vivisect/mutate/experiment on/shoot normal human and other sparks as they are to waste Clanks/Jaegers/Revenants/Monsters/etc and eagerly "improve" themselves. So, in a way, the trope is subverted, since Sparks treat all intelligent beings equally. Equally expendable, in this case.
The clanks, for the most part are mindless, order-following robots. However even the more sentient ones, like Dingbot Prime or the Muses (who even look human) aren't exempt from being dismantled in the name of study and/or improvement. Another notable instance is in the Sturmhalten arc of the comic when the Anevka puppet, which had gained its own sentience by the time the person it was built for died, is deactivated by her 'brother', as seen thesestrips. Possibly an aversion, though, as he admits it was much harder than he thought it would be.
Heterodyne Show treat Moxana with reverence—then again, it's harder to see Muses as "mere walking mechanisms" than not to.
Othar Tryggvassen, Gentleman Adventurer! is far from a normal human. Klaus already had a good reason to kill him—his "Mission" of exterminating Sparks—but was too pragmatic and curious to do it without learning anything.
Othar himself isn't nice with nonhumans (see the conclusion on the next page); his role in the hanged Jägers incident confirms this in-continuity.
Jägerkin are an artificial race of constructs created and maintained by the Heterodynes. They're modified humans, but never grow old and get severe injuries fixed again and again. In the town of Zumzum, the townspeople hang Jägers just for passing through. They do have fangs and claws and odd skin colors and were rather bloodthirsty enemy soldiers once, but is that the reason to hang them now? Not that it ''worked'', anyway.
Despite featuring a wide array of non-human creatures and plenty of violence, Sluggy Freelance usually avoids this issue by treating all life, human and non-, with varying degrees of respect and irreverance depending on the tone of the story. It is parodied in thesestrips, however, and gets played straight in the "Aylee" chapter, where, even though most ghouls seem only semi-sentient and attack humans on sight, Aylee still feels uncomfortable with the lethal practical jokes she and Torg play on them. This is made worse for her when she discovers that the "ghouls" are actually aliens of her own species.
Dr. McNinja also plows mercilessly through zombies.
In Gnoph, the Gnoph symbiotes were created to be organic computers. While some of them are sentient, they are generally not regarded as such. In the most notable instance, a doctor casually murders a Gnoph which has become quite sympathetic to the audience and then is bewildered by the heroes' horrified reactions. To her, it was just like throwing away an obsolete computer: "I've seen guys be that emotional over cars, but never a gnoph. It was as though I killed his dog or something." The doctor genuinely didn't know the Gnoph was sentient, but is also portrayed as being unethical and amoral, and in any case the heroes are very upset over the death. Very.
Deconstructed in Alien Dice as more of a 'what measure is a sentient being with free will?' The Dice (semi-sentient creatures such as cats who are transformed into self aware creatures), despite sometimes displaying intelligence greater than their owners, are used, recycled, and in some cases destroyed because it's convenient for the owners. Even more atrocious is the dehumanization of the Indentured Players (who are sentient aliens turned into Dice), who lose the right to choose mates or claim their offspring, among other things. Some characters see the Dice as sentient, but others see them little more than objects to be used at will.
A major portion of the backplot of Terinu as one of the secrets of the rebellion against the Varn was the destruction of their source of power. Which just happened to be composed of cute little humanoids uplifted from animals. Though designed to be subservient, the Ferin were sentient beings, and the wholesale slaughter by the humans was essentially a genocide.
The rights of non-humans are an important theme in Freefall, with a squid-like alien protagonist, an anthropomorphic, intelligent, genetically engineered wolf who is technically still property, and a host of apparently sentient robots struggling with or ignoring the three robotics laws. In one story arc, robots have been dismantled against their will. As Sam asks: is this a crime or simply overly aggressive recycling? (cue the Ironic Echo two strips later)
Most robots, it should be noticed, do NOT have the three laws. This is because the Laws have a major flaw- the laws are phrased in absolute terms and incautiously throw around the word "human." Thus, force a Three-Laws compliant robot to choose between committing genocide of a nonhuman race and letting a human's feelings get hurt...
In an earlier scene Sam is surprised to learn that robots are taking an interest in religious texts. "What do they want with those?" he wonders. "Robots do not have souls. Or do they?" To which the bible salesman answers with a wry smile: "I think that is what they are trying to find out."
There's also a strip where Sam calls Florence a slave, and mentions that in his home planet such thing wouldn't be allowed; Florence angrily argues that she is not a slave, but concedes that she technically has no right to property, free travel or vote. As for robots, some consider themselves property and would gladly argue against anybody trying to free them.
In Schlock Mercenary: "Food that talks is not food." If it's talking to you, odds are that it's going to get treated as having the exact same rights as everyone else, whether clone, artificial intelligence, or alien. Given the subject matter, those 'rights' include the right to be blown to fine chunks by the Heroic Comedic Sociopath protagonists or whoever the current baddies are. There's still the question if a goon doesn't get a chance to say anything before being eaten.
To Schlock himself, food that talks can be food. Then again, that's just one of his many ways of disposing of his enemies.
The 'food that talks' thing is taught to a race of alien hunter-gatherers who are encountering aliens for the first time, when the other guys are known to be hostile, then all stops are out. Besides, a lot of the antagonists are humans, while a fair few of the crew are alien.
This serves to make Ventura's views on robots all the more disturbing. In that she probably won't mind doing the same to organic folk if she could.
Para Ventura: It sounds like you treat robots as if they're people.
Ennesby: Oh, I don't know. He treats people like they're robots, so it gets kind of hard to tell what he's thinking.
Para Ventura: [...] You treat your machines well. I think I may have to like you.
AIs are also regulated a bit more heavily than humans apparently, since no humans have yet been sued for being too intelligent.
Subverted in minus.here, where she ends up apologizing.
In El Goonish Shive the main restriction aliens and magical creatures deal with is their respective Masquerades. Ellen bears the brunt of this trope, having been created by magic. While the main cast readily accepts her as one of their own, the wizard who enchanted the artifact that created her awakens to hunt her down. His reasoning? Anything created by the artifact is unnatural, and therefore must be destroyed. Even though Ellen has been treated as a separate person ever since her creation and developed a distinct personality to separate herself from Elliot. Nanase sums it up pretty well here and here.
Also played straight for the first boss, the goo.
This page of Gunnerkrigg Court shows Jack Hyland brutally wrecking a robot security guard, much to Antimony's horror. His response is a callous "So what? It's just a dumb robot." Even though the series has shown that robots are quite clearly sapient and capable of emotion. It also shows his increasingly deteriorating mental state as he was far nicer to robots earlier in the comic.
According to the student handbook, it's official Court policy to "Remind the robot that you are a higher order of being, while it is merely an appliance." Annie and Kat are among those who consistently view the Court robots as people.
Also, according to Muut and then Word of Tom, there is no psychopomp for robots. By contrast, there is a psychopomp for insects. However, it's revealed in a later chapter that robots don't have the same concept of "death" as flesh-and-blood beings, considering themselves to be "dead" whenever they are shut off. If robots do have souls, then, like Annie's mum, there may be no reason to take the soul of a being who can, in theory, resurrect indefinitely.
In Off-White, when a group of sledders became closed in and ran out of food, the sapient dogs were the first to go because of this trope. One of the sledders even says "people are always more important."
In Homestuck: Dirk has an auto-responder program that's effectively a duplicate of his brain at age 13, and a lot of conversations about him revolve around the ethics of what one does when they have what is essentially a robotic clone of themselves. Dirk encourages AR to be as active as possible, as he considers stifling something that is very much alive to be And I Must Scream. Jake initially disrespects AR, believing it to not have feelings, but AR gets significantly offended by that, claiming that it is mentally as human as Jake is, and a later scene shows that AR might have genuine romantic feelings (though he admits that they might be fake just to fuck with Dirk).
The comic in general heavily averts this trope. The numerous races that inhabit Skaia, Prospit, Derse, and the Lands (carapacians, consorts, underlings, etc.) are almost all just as sentient as the protagonists. The kids treat carapaces and consorts as equals (though it's noted that consorts, while sentient, aren't very smart) and are only shown attacking underlings like imps, liches, and ogres when they attack first (indeed there are several times where underlings are shown either choosing not to attack the players or actually befriending them and are thus spared).
The trolls aren't so kind towards other sentients (at first) but this is only because of their upbringing; the Condesce essentially twisted her own race into a galaxy conqueringrace of xenophobes and casually genocides or enslaves every other sentient race encountered. In fact she doesn't even seem to consider some other trolls sentient or equal. Her Fantastic Caste System created around the hemospectrum basically lets trolls with high-ranking blood colors do whatever they want to trolls with low-ranking colors, who are expected to just lie down and take it. Hell the Condesce goes so far with this as to declare the disabled and crippled to be unworthy of life; if you have even a tiny genetic defect in troll society you're culled before adulthood just because the Condesce doesn't want you breeding.
Paranormal Mystery Squad opens with the team hampered by "new regulations" against "cryptoslaughter"; even after this, Steph keeps killing cryptids willy-nilly for a little while, and the only consequence is a series of steep fines. This despite the fact that most cryptids are clearly sapient, and for most of the standalone series, there are two on the four-person team.
The Mons featured in But I'm a Cat Person have personalities that change from owner to owner, limited free will, and compulsive obedience. Different characters may argue they should be given the same rights as humans, the limited protections of animals, or no more regulation than very sophisticated computers.
Project Skin Horse exists to avert this trope. Their job is to ensure that nonhuman sapients get their civil rights too, although successes are... mixed.
Magick Chicks parodies the Sailor Moon example when a former magical girl complains that she never understood why her evil nemesis's monsters always exploded after being defeated in a manner that makes it quite clear that she really wished they hadn't.
Dakota: "I don't know why they needed to do that. I mean, they were creatures, but they were like people too. 'Nooo, you have defeated me...' Boom."
In The Glass Scientists, the police treats werewolf as a non-human beast that should be locked up and the mob tries to kill him even before that.
The protagonists of DNA are genetically engineered furry children with super powers. They are considered experiments rather than people. This like likely part of the reason why the story takes place on an isolated island, so that the scientist can get away with not giving them the same rights as humans. Jay tries to keep them from being abused but he is far from being a good caretaker. Rigel admits that the reason why he bullies Orion is to feel better because he hates how he is treated.
Part of the Doorman's lecture involves the fact that Isaac called him his "shortcut", labeling him for his utility rather than his own being, even if Isaac didn't mean anything by it.
Doorman: You refer to me by my function ...how ...human.
A large part of Eightfold's departure stems from the fact that Isabel unconsciously considers her more of an item than an equal.
Daughter of the Lilies: Cave elves are written off as non-sapient monsters even though they have a language and an internal society. On the other hand, they're fine with eating people alive. As a cave elf herself, Thistle has a lot of anxiety over being a "monster".
In the comic Rocket Member, gijinka (which are humanoid beings with special powers and Pokémon traits) deal with issues concerning their humanity. The Yakuza/The Mafia Team Rocket outright use Poké Balls to enslave them. This is illegal but nevertheless widespread.