There is way more rape in horror movies than there are rapists. It is so often cartoonish monsters, or bad guys so evil that anyone can look at them with disgust. I think there is a place in horror for depictions of rapists that are a little closer to the truth - rapists who have excuses for themselves, who don't see themselves as evil at all.
Having a rapist like that in a movie might hit a nerve with someone, hit a little too close to home. It might make it harder for real live men to believe those self-justifications if they see them echoed on the screen so clearly connected to the horror of rape. If movie rapists aren't always just monsters that look nothing like real human beings, if they are monstrous because of their actions and the effect of their actions on others, it might occur to more men that what they're thinking about is actually rape.