Yaoi's problem

Gentle Cage - You Shiizaki, Kumiko Sasaki, Bianca Jarvis Ai No Kusabi The Space Between Volume 1: Stranger (Yaoi Novel) (v. 1) - Reiko Yoshihara Ai no Kusabi Vol. 2: Destiny - Rieko Yoshihara, Katsumi Michihara, Kelly Quine

Why is it when I read or watch a BL/yaoi story, it ALWAYS has to have some kind of sexual assault or rape scene in. Even Love Stage which comes off more as fluff has a scene in it where Ryouma has to prove to his brain that Izumi is a guy and "OH MAH GAWDS I AM A FERAL BEAST AND CANNOT CONTROL MYSELF!" after he tears off his clothes... and we are supposed to think men are rational beings capable of logic.