everyone is connected.

Roy Thomas (1949-2004). Canadian indigenous artist

This is a massive part of why Argilla struggles with it, right? To be a cannibal is to do something inhuman, to cannibalize someone is to dehumanize them. Yet because of the virus, if she refuses to commit cannibalism, she will eventually very literally be forced to transform into something non-human, lose her mind, and be reduced to only her hunger.

Meanwhile if you take a character like say, Mick, he'll happily feed on his own soldiers given any reason to do so, he views them as mere objects, as stepping stones to his goals that he is free to do whatever he wants with. He is above them, they are below him.

Heat as well, he takes pretty quickly to viewing anyone who isn't on his side as food. Their humanity doesn't matter to him, they are food and he is hungry. (I'd be remiss here not to take note of how his real life counterpart's major canonical relationships largely involve dehumanization, from his deification of his own sister, his everything with Sera, and the way he projects the harms of the entire Karma Society onto Sheffield but expanding further upon this is a topic for another day and post)

Now even after Argilla is forced to accept that she cannot avoid cannibalism forever, we still have the scene where she is forced to kill Jinana and she refuses to eat her after the fact. That is someone she treasured dearly and she cannot bring herself to dehumanize her like that. Heat on the other hand tries to push her to, Jinana is no longer a person but a corpse, which she responds to by smacking him and leaving without desecrating Jinana's body. Gale soon after steps on this landmine as well, treating the situation in a cold, detached manner and completely failing to understand why Argilla is behaving this way. He's still doing his best to operate under the understanding of the world they've lived in thus far, one where they are nearly all ultimately expendable pawns to be cut when it is strategic to do so.

That's also something he is forced to deal with later on when he quickly grows attached to Lupa before being forced to kill him as well, mirroring what happened previously between Argilla and Jinana. As he is dying, Lupa tells him to eat his body and while Gale does comply here it's pretty clear that this is a horrifying experience for him, one which infuriates him and causes him to swear to make the one who afflicted them with this cursed power pay. Gale is forced to truly understand this as the dehumanizing act that it is here.

And then we have DDSAT2

Pretty immediately, we're introduced to the Karma Society and the Underground. The people underground are an oppressed underclass, with things going so far that they are freely captured to be harvested for meat to feed the upper class soldiers. What is also made clear as the Embryon progress to the facility that people are brought to to be killed and butchered is that the Karma soldiers do struggle with this, they cannot bring themselves to just go and eat dead bodies so this is all handled out of sight. They have a factory devoted to automatically preparing and processing these human bodies into canned meat, completely unrecognizable as having ever been human in the first place. This is what is required for these people to cope with the fact that they kill and eat other people.

(Also of note is how even the Embryon have limits here— hunt skills do not work on human enemies and enemies killed while in human form do not grant any AP. They may not go to the extent the soldiers do to deal with the fact that these are human beings they are eating but they still draw this line.)

One can also point out that this virus originated from the Karma Society using children as fodder to try and advance their understanding of the world, little expendable lab rats numbered by the order they were thrown into the woodchipper. It is a curse bestowed upon Sheffield by God when Sera, and by extension God, are made to witness his true feelings about her and how readily he has O'Brien killed for his attempt at standing against treating her life as expendable. This curse is then tested and refined by the very group which ultimately produced all of the conditions required for it to come into existence in the first place.