ok this is 10000% me projecting my own inhumanity but consider: he/it hux
the Realization doesn't happen immediately. like--imagine that he's maybe 25 and he's climbed up far enough in the ranks that people have stopped trying to emasculate him, at least to his face, and he thinks this is it, people will actually properly recognize me as a man, my gender troubles are over, surely there will be no further complications on this front, and then someone like pryde refers to him as a monster or a droid or even a thing and he's just like
he doesn't object. he barely registers the fact that it was meant as an insult. rae pulls him aside afterwards, clearly worried, and he doesn't know how to explain to her that it was--comfortable, like a well-tailored uniform, doesn't even know how to explain it to himself, and in desperation he asks her if she thinks he's human and she says of course you're human, armitage, and he knows that it's meant to comfort him but he just. it's just. it's uncomfortable.
he doesn't bring it up again. rae understands a lot of things, even things no one else seems to get, but this is not one of them.
but it stays with him, that discomfiting discomfort. what does it mean, that the idea of being human leaves him feeling sick? does he really hate himself that much? does he want to be an alien? a machine? an animal? does it matter? it shouldn't--he shouldn't feel like this, he should want to be human, should want to conform, to measure up, to be normal, but--but no matter how many years he spends trying and trying it still just feels wrong.
he meets phasma. they kill brendol. and with that secret between them--that promise of mutually assured destruction--they begin to share others, dangerous and mundane and strange, and deep into the night one night, nearly a decade later, he once more dares to speak it aloud:
sometimes i don't want to be human.
and phasma turns to him in that way that means that even armitage can tell she's looking him in the face, even with her helmet on, and for moments and moments she says nothing, until:
sometimes i want to be a beetle, she replies.
and armitage finds himself smiling, because there are many things that phasma doesn't understand, but this is not one of them.