Made A Discord Server

i'm genuinely curious as to why people like those tropes. i was reading "love stage" and the author was indirectly talking about how they were afraid to make it a switch couple because it'd get less sales. like wtf?! gay relationships r not hyper-masculine man and a girl with a dick. can someone PLEASE give me a reasonable reason as to why these tropes exist and why switch couples are looked down upon? i'm on the verge of losing my marbles