You really think it's all learned?
Who does the teaching?

I have no scientific proof (though I should research) but if we are willing to see rape as a type of violence, why can't we ascribe the same traits to it?

Most agree that some people have a higher propensity for alcoholism, aggression, abuse etc tell me how you think rape differs?
Lets say in a close group of guy friends who grew up together in similar environments there is one whose sexual aggression has always been questionable. The type to grab a girl's ass and laugh or strong arm a chick in the club. Everybody else has no problem walking the fine line except for him? Are you saying there is no chance his tendency is partially innate?

Btw as I have made clear before, I am in no way excusing him just saying he might be built like that and the basic lessons we give young boys will not suffice for him.