Responses

I think it's caused by the repetition of such uke and seme, where uke is "cute" and "naif" while the seme is kind of obsessed. By seeing some couple with the same traits, some readers may form categories : the uke is the cuter one, the girly one, the weak one, the nerdy one, the small one while the seme is the manly one. It kind of rebut me too. I like seeing more diversity, or reverse couple sometimes. I just hope people don't confuse yaoi and reality.
You would think people who read yaoi are open minded. Instead so many have antiquated, heteronormative views of seme/ uke roles and acceptable behavior.