I think the majority of the people who read BLs with rape included are sick people or people who are too young to understand the gravity of the offense.
I remember that I started out young when I first started reading mangas/manhwas/manhuas. Even if they weren't BL, I would read romance with rape or sexual assault. I wouldn't be okay with it, since I knew that the act itself was bad, but I didn't drop the story immediately like I should have. Instead, I would continue reading it until I finished it, when the couple would get together, and all was forgiven between the two. Sometimes, I would also forgive the offender or I would get frustrated, it would depend on how bad it was, which ALL SA or rape is bad, but as I kid, I guess my tolerance was different from how it is now.
Now I'm older and know better, so any mention of rape, non con, or sexual assault/harrassment between the MCs, and I'm dropping it on the spot.
I also had a time where I would continue stories with rape and noncon etc. And as you also mentioned I also sometimes forgave them. Maybe because I was also a bit to young to fully understand when someone really gives their consent. Since most of the times the characters would gloss over it and I would also think it's fine. But like you, I also immediately drop stories with rape now.
And btw thank you for your reply (づ ̄ ³ ̄)づ
I often come across yaoi with rape in them and I absolutely hate that. I can't imagine someone liking that story. But the most awful thing is when I scroll down to the comments and I see people say that they really liked it an think it was cute!!?? Like what??? So I'm just curious how these people could like this