I really struggle with this issue. In me it plays out as a struggle between my undergraduate and graduate degrees. In undergrad I studied Social Psychology and was particularly focused on Social Learning Theory, the theory that produced the
bobo doll studies that introduced the idea that media can induce violence in children. Naturally I believe those studies have validity. One of my professors even owned one of the original bobo dolls, a gift from the man who did the study.
In my professional work with the American Library Association I have focused on intellectual freedom. In fact, I just accepted a seat on the Reference and User Services Association intellectual freedom committee that I chaired for three years before timing out some years ago. As a librarian and intellectual freedom advocate I abhor the blaming of books, tv, music and films for acts of violence and any attempt to censor based on them. I always want to point to the thousands of people who watch the same thing and don't commit violent acts.
Honestly I have no answer to this question. I do believe that if you have no urge toward violence or healthy coping behaviors to deal with your urges you will not act out no matter what you watch. But I do believe we learn from watching other people, in person or through media. Hell, I'm the youngest of nine children, I
live learning from others' mistakes. It's still one of my primary methods of learning and dealing with situations. So I just sit here and argue with myself and feel a bit helpless when these ideas come up.