I am a simple person and I take it simple. I like genderbend because something about the man becoming a woman and experience being a woman is just some weird fantasy that I like. I am not gay, I like girls, but I don't see myself doing it with another girl if I suddenly become a woman either(maybe because I still see that me in 3rd person and not able to see it from 1st person). Like, that kind of liking changed with the brain, as you said. Unless it is a person that you love by personality and not just body, it is kinda ass to think you still like the opposite gender when you are that gender now.
Again, I am not gay. The most I tried was reading yuri and yaoi hentai, and also watching lesbian porn. It wasn't stimulating to me in anyway. In case there are westerners reading, no I am not a homophobe, I support LGBT as long as it is good and not annoying, but I myself just doesn't have any interest in that sort. I like genderbend for the weird straight romance that it provides. The MC here became a woman and still wants to like woman because he used to be a man, but in my eyes she is just gay, me no likey gae stuff. Many people here are here because of the yuri as well as them not liking the genderbend, me feel like me stepped in enemy territory and kinda agitated, sorry bout dat.