I read through the document. The research conducted by those cited is not the only research on the subject out there. Here's a link:
http://whyfiles.org/165video_violence/3.html (also contains a link to "the flipside of the argument", as in the side taken by the document you provided).
When I say science has not been able to provide us with anything conclusive on the matter, I mean science has yielded contradictive results and thus the big questions remain unanswered.
I'm not saying there has to be a direct link. I'm not even saying there
is a link. I sure as hell am not shifting people's responsibility of their actions over to videogames or TV. My common sense simply can't get over the thought that maybe constant exposure to realistically depicted murders, rapes, thefts and whatnot on TV and playing them out in videogames isn't completely harmless even when you can distinguish them from reality.