Probably because the writer had more screentime than the older bro plus
-SPOILER for those who haven't read the raws-
we first saw the older bro as an uke when he slept with the writer when they were younger. Also, he's kind of more feminine compared to the writer and sometimes more than the uke. He's really pretty too. Don't worry I felt the same way at first so I understand lol. I had to consciously remind myself how much of a trash the writer is so I could appreciate the main couple.
Yeah I can totally understand that. the UkeXUke Dynamic doesn't really work for me but it's healthy the 2 main characters seem to love each other so I guess I'll take it even if I don't ship it like that ╮(￣▽￣)╭
This isn't really a spoiler but in the raws the little brother and the older brother have like no chemistry together even thought there romantically together I personally don't ship but the little brother does have LOT chemistry with the writer but is toxic AF a rapist and a mass manipulator. I think there's weirdly something wrong with me thinking there were going to end up together ╥﹏╥