Personal experience here, and I've got to go with all those who say that if a person him or her self is not predisposed to violence - they will not be violent. I had no mother and an alcoholic father.
I, as stated, come from a severely disadvantage and violent background, went to the roughest high school in my city, where the student teachers refused to come for practice, at 10.1/2, and learned to fight at a very early age. Just getting home from school often involved a form of gang warfare - I never belonged to a gang.
Despite this 'nurturing' I have always been a person who will not initiate violence - I have always regarded it as the last resort of the incompetent, and the proof of that is that, even in my 50's, I tamed a violent major city club with a totally non-violent approach.
Got all that?
So - no amount of porn or horror movies or action movies or whatever is going to change the simple, unassailable fact that I personally am not a violent person, and therefore, like the very vast majority of similar people, it is not really possible for those things to 'cause' violence.
It's a lie.
On the other hand, one thing that I know can cause ordinary people such as myself to embark upon violence is the application of violence against them for no proper reason. You should all know what I'm talking about here by now! State-sponsored violence in the name of a ridiculous social agenda
On another subject - the men in porn are just as much objects as the women - I simply could never be bothered watching it. And I have no religious affiliations, either.