damn son looking good in drag when i was reading ch4, i wondered if he's only into fat ...

I think trauma? Because he is being raped by his "ex" the person he "dated" and comparing to Kou he was very kind even though he is rude. He doesnt blackmail a person to be able to date. So he compared it that he likes Kou better who is fat. And so he liked fat people much better because it reminded him of how kind Kou is. Thats just my thought...