
This isn't the first time that happened in Yaoi Mangas or Manhwas/Webtoons.
I ve read other earlier Korean BL Webtoons where the characters are in more or less grounded and interesting situations but somewhere in the middle of a season or later chapters some characters be it minor, supportive or antagonistic get rapey and become really evil out of nowhere. It is like they turn 180°.
There is the 90s show Melrose Place where literally every single character becomes insane and evil in a very bizarre twist. The reason why it was written that way is because to gain more viewership through shock values and most of the actors wanted to play the bad guy.
Here is a fact: Sexual Assault and rape is unfortunately part of the soapy melodramatic storytelling. It is indeed a romanticed toxic trope!
On the other hand, the webtoon Mr. 100% Perfect is more nuanced and doesn't display any these classic bad yaoi cliches.
For example, the MC gets involved with a fuckboy and enemy of the ML. MC/Uke gets little drunk, Fuckboy wants to seduce him but MC reject him nontheless and accidently broke his nose, FB is annoyed but lets him go, he doesn't even attempt to rape him at all, MC apologizes and meets with ML to have real talk about their relationship and problems.
What surprises me the most is that the bad fuckboy isn't that antagonistic or sociopathic and he can behave rationally. He can behave like an asshole sometimes but he can be very civilized.

Read Mr. 100% Perfect.
The so called antagonist isn't for once badshit sociopathic or rapey.
He is a mean fuckboy but he can behave very decent and rational. We see he is not cocky invulerable.
And the MCs actually have the intend to communicate with each other without that much dramatic twists or stupid misunderstandings like in any soap operas or telenovelas!

I know it's not the first lol I read a lot and I've dropped a lot of stories just because this trope. most of the time they are just unnecessary when the author could have just gone on a different route if they wanted to give the mcs a problem of a difficult time..sighh. I'm reading mr 100% too but I'm still wary of that fuckboy . also which is why i don't like much of american dramas they put too much unnecessary shock factors

Even Asian dramas have also shock factors. I also watched enough Chinese, Hong Kong, Japanese, Thai and Korean TVs and they also showcase sometimes unexpected shocking twists - Not as explicit brutal like American shows but still...
For instance, I remember Asian shows titled under the genre Romance and Comedy but suddenly the appearance a dangerous stalker, rapist, psychopath ex-partner, evil family member, unexpected death of a character, criminal from the past etc.
It's like they added just another genre to make the story more edgier.
Sorry to say this but I get the impression that many Asian women are depicted so much weaker and helpless compared to Western women.
I don't know which American dramas you have watched but there lots of diverse shows that are tyring to be different from others.
In chapter 44 Suha gets bloody physically and sexually assaulted by the gray-haired ex-sexpartner and red-haired older Brother of Jiwoon :(((
Was this sudden development/direction so neccessary??? Two psycho sadists ganging up on Suha..... I am appalled and speechless by this scene...
https://tkor.pro/%EB%82%98%EC%9D%98_%EC%88%98%ED%95%98_44%ED%99%94.html