Not that if they weren't it would mean anything, but that is a matter of fact. Certainly, porn will not always cause rape, but that does not mean it never does, either. Not everyone who gets an education goes out and becomes a brain surgeon, either. And the explanation for the difference between those who become brain surgeons and those who don't is human volition. The same goes for rape.
Pornography is a textbook on how to victimize women sexually.
Saying that pornography does not cause rape is like saying that reading an encyclopedia will not make you educated. No, saying that pornography does not cause rape is like saying that reading an entry in the encyclopedia about entymology does not make you an entymologist. Anyway, the vast majority of sex scenes in pornography are portrayed as being voluntary. Not that if they weren't it would mean anything, but that is a matter of fact. Not everyone who gets an education goes out and becomes a brain surgeon, either.