If violent games, movies, music, etc. made children do violent things, then I would be the most evil, blood-thirsty maniac on the planet right now. Guess what? I’m not.
Also, there would have been no violence in human history prior to all of these kick-ass forms of entertainment. Whoops! There was, and tons of it. What was the cause? Religion, lust for power, greed, being overall coo-coo for Cocoa Puffs. Not video games, movies, or music.
People need to quit pointing the finger at everything else when this subject comes up and take some responsibility for their severe lack of parenting skills, etc, like the mother who clearly had a nutbar in her house so instead of getting him help, she stocked her house full of easily-accessible guns. How did video games cause that?