You want to bet? The one who play these type of games are more dangerous and cunning if they do live it out and go on a massacre killing than a person who never laid eyes on these type of games. Maybe you haven't met any fuck up teenagers yet. I'm pretty sure there are some that are spawn from these type of games. I'm pretty sure guys in the military hate these type of shoot them up games. [sarcasm]
No, the more dangerous ones are those who spend time educating themselves on subjects like building bombs, and developing plans to attack an isolated group of people who have no support available from law enforcement.
Playing CoD or WoW had no effect on his ability to carry out the attacks. Continuing to pretend that video games and violence on TV are the issues when tragic events like this happen is a barrier to prevention, which is why I find it so offensive.