sexual assault can make you orgasm though thats the thing. it still doesnt mean that you enjoyed it, just that your body orgasmed. a lot of victims think that since they orgasmed while being assaulted, they must've enjoyed it and therefore it wasn't truly rape (again it doesnt matter if you orgasmed or not its still rape because you didn't consent). what you described is a harmful mentality that a lot of people have i think.
i think you're right about bl authors always making it so that the victim feels good while being sa'd because that isn't true a lot of the time irl. but it still is possible and not that out of the ordinary is what I'm trying to say.
The fact that authors show that rp makes you feel good at the end is amazing like wtf bro since when did sexual assault made u feel good ???