I get what you say.
The autor shows us a really obvious contrast when you see how San treats the MC so nice and wants him to feel good, and on the other side we have the second couple that one rapes the other.
I think this is intentional, as you mentioned, I do think she has a motive of why she decided to portrait it like that when she showed us that there is a proper way to treat your partner.
We still don't know what the hell happened in the past, all we know is they all are traumatized by something, and one of them doesnt even remember!!
(not that i'm defending the act of rape, but saying AT LEAST we could UNDERSTAND why he acts that way)
Really disappointed with the rape scene, there's so many in the BL gnere and ngl there are a lot of times when I don't mind to be brutally honest? But I don't know why, it's really bothering me here... I don't know if it's because of the colors and details... it just feels more graphic and violent... the way it's presented, it's like the author wanted it to be titillating, but I just felt uncomfortable, sorry for 704 and wanted it to stop as soon as possible...