First half of chapter made sense. Second half were a character saying that because his analogy was slightly flawed (should have been a village of yokai men she is tossed into) his entire argument is flawed? And he agrees? That's not how debates work. An argument might be flawed or even outright wrong, but that doesnt serve as a proof that the standpoint it tried to defend is wrong. While not the same thing, its equivalent to saying a devils proof is "solved" (existence is disproven) if the proof trying prove something exists was fabricated. It simply put doesn't work that way.
His points are very valid. He is essentially kidnapped and put into a situation where suddenly he is surrounded by "enemies" who is essentially trying to exploit his body and force him to do what they order him to, a situation where its very natural to develop a "me vs them" mindset. That he got over that as easy as he did is strange already (stockholms syndrome?), but might be somewhat because the authority-figure in his life telling him to accept it (his dad). But even then it is quite the jump to suddenly willingly procreating with strangers for the sake of children, strangers who only see value in his body as a vessel for making babies and none in him as a person (except for a certain snake).
Basically, his situation is just like he described, one where he is taken to unknown lands, surrounded by unknown strangers and asked to dedicate his life and body to them no matter what his feelings are on the matter (why does this make me think of slavery?). And they expect him to feel a sense of family and community with them just because he shares some arbitrary racial trait (lets not replace "youkai" with "white", thats a whole other can of worms better left unopened).