Well I haven't read straight romance Manga for years esp for older audience. But my theory is that, since especially in Eastern part of world homosexuality is something shameful or to make jokes about. Naturally there is frustration built from public pressure. Many public proper people either straight or forcing themselves to be straight. But rejected ones have lost their pride already being homosexuality doesn't add anything fresh. Or they are too powerful and thinking they're alpha male. That kind of pride often brings frustration to keep up face and finds outlet in wrath and violence. Then they can lose face at some point and become a reject.
This is all my reasoning about this. Might be wrong.
---------
Btw all cultures make jokes about prostitutes in profanity but hardly anyone raises any voice, while some people make their living from that only and no other career while its been used by *decent people*
For so many mangas and webtoons to have rape and love go hand to hand so often I wonder about the authors who write and draw these things. Whats going on in their lives? do they have relationships like this? whats up with Asia and rape culture?