This actually reminds of a story I saw on CNN yesterday about the lack of proper defense for the alleged 9/11 terrorists in their upcoming trial. A political scientist claimed that this is the worst thing the US could do if they want "revenge" on the terrorists, because if they are convicted without having a proper defense, this just removes all credibility from the process. I think there's a similar thing going on with these video game experiments. I do not really doubt that there's a grain of truth in the result, but when making such elementary methodological mistakes and mind-numbing generalization, they really are doing themselves a disservice -- it just removes all credibility from the process. I'm not just picking on this experiment in particular, but I've seen a lot of the same problems with the most cited experiments on violence in computer games, including the interesting but far from conclusive research by Craig Anderson. What's worse it that the media, when picking up these stories, usually omit any caveats and methodological footnotes, which results in the kinds of headlines that ultimately might sway the public opinion.
I think the sensible thing to do is to not jump to conlusion on either side. Allow me to make a sweeping generalization on my own: On the one hand, gamers and hackers too often claim that all kinds of so-called piracy is good and that virtual violence has nothing at all to do with real violence, whereas policy makers and media all too often claim that piracy is just ultimately a form of selfishness and that every murderer out there has been playing violent video games (which, even when true, could by at any end of the causal chain). Neither is true, and in championing either extreme it just makes it more difficult for the sound and carefully weighed considerations to come to the front.
In the words of Jascha Heifetz (which just happened to be the quote of the day on my Google home portal): "No matter what side of the argument you are on, you always find people on your side that you wish were on the other."