[Nerull]

Actually, I would argue the opposite is true. There would not be violent games out there if there was not a demand for violence; if everyone wanted non-violent games, then the market would be flooded with them instead. Same thing with movies (getting more and more violent), television (ditto), etc. Does it have an effect? Sure. Seeing something over and over again desensitizes you to it, making it not as shocking, etc. But, those people that commit acts of violence after playing violent games were already heading down that path anyway, in most cases. But the big thing about the media is that it flows to where the consumers are, as do all businesses.