In my youth, I was the first to defend video-games against those such as Jack Thompson and his ilk; but there is definitely something to be said for their arguments.
In the past, people were not as exposed to this level of violence as we are today. One couldn't turn on a television and see a mother being [censored] in a movie or a Father being cut up by a possessed doll. One couldn't fire up an Xbox and start shooting the "baddies", as though they're really that bad as opposed to the player.
Depending on the period and location, war could be as prevalent as it is now, or as peaceful. But let's make something clear, the United States has been in constant conflict for over 200 years. I do not think this is as much a contributing factor as the direct influx of violence that pervades our information though.
People have always been violent, but they can become more violent and more ignorant depending upon where the majority of their information is derived from. Therefore, I do think video-games, movies, and music can be a major contributing factor toward the level of violence in our neighborhoods today.