What Tartan_Ninja says is true (damn it, didn't there use to be a "quote" button on here? I don't know shit about HTML). But it's not hard for kids to get hold of games without their parents' consent (through friends etc), and I think STUDIES HAVE SHOWN* a strong correlation between playing violent games and violent, disruptive real-world behaviour (maybe not mass shootings, but still). I definitely feel more aggressive after I've played something like Condemned 2 for a while, and it scares me a bit.
*That's what I read; maybe I'm being brainwashed...