I dont think so. Historically speaking, our society isnt any more violent than it was 100 years ago. Unlike 100 years ago, however, we have the media to showing it to us 24/7

I read somewhere that vegetarians are less violent and what I read attributed it to eating less hormones and steroids in meat. But on the other hand, in my opinion, vegetarians alot of times are just "nicer" to begin with because they care about animals.
Maybe they should do a study on violence compareing vegetarians to meat eaters.