The fact that this is fiction is both obvious and irrelevant. The cliche yaoi rape trope was not created for Western audiences. It was written for women in a culture where it wasn't acceptable that good girls openly like sex. So as these women identify with the uke/neko, sex must be forced....no means yes, etc. etc. We are not the paying audience so we can not influence mangaka.
We all have a right to our opinions, however. I'm not looking down on people like who may enjoy this trope.
Art is an expression/reflection of life. Are we really objecting to rape tropes or are we objecting that other cultures did not get the sexual revolution memo? Even in Western cultures, rape fantasies are not uncommon though they may be portrayed differently in art.
Imho, I want to read fiction where tropes and cliches are creatively played with rather than thrown into a story to complete some formula. I think if a story has rape, it should be critical to the plot and the story should avoid glossing over the traumatic effects to be authentic but I'm not here to convince people to see it my way, I'm just venting.
In the case of koisuru_boukun...obviously their relationship wouldn't have begun if not for the initial drugged rape and subsequent blackmail rape so I get why it was put there BUT I find the rape to love trope cringe. Also senpai was a homophobe there is no way he would not have had some ptsd. I felt so bad for him when he cleaned his asshole of semen the morning after.
Koisuru Boukun