again we see them putting blame on a rockstar who yes makes violent video games, but in this case I don't think this would have been prevented even if his parents did monitor his gaming habits. I think in this case he could have learned the same things from playing a lot of different games, for example need for speed, which for the most part are all E rated games, and it is the same thing for a lot of different racing games that he could have easily gotten and then blamed his learning to on.
In the end this just seems to a case of parents that aren't paying attention and trying to blame every one but them selves.