@Wuzzy If I'm asexual, but don't know it (yet) and feel pressured by society to have sex, I will say yes to the person I love and mean it - even though I actually don't want sex.
So now you're saying it's never okay to have sex with people against their will. So in other words sex is always rape, because you can never know, if the other person wants it.
I still don't see a hard red line here.