I understand your angle Scrubcedar, I don't agree with it, but I see your point.
The way I see it, no matter how many games I played, when I actually got my hands on a real rifle, it didn't help me one bit in terms of marksmanship. It was practice and training. Sure the video games allow you to practice hand and eye coordination, but ultimately IMO it has little if any actual affects on the individuals ability to actually harm someone. The concern I see people having is the psychological desensitization of young adolescent children to young adults and how they become numb to the idea of the loss of life.
The way I see it, in the end, regardless of what kind of media that is placed before our children, if they are so disturbed and inclined to handle their problems violently (It's not always that transparent by the way) with or without the influence of video games, movies, literature violent or otherwise, that individual needs to make the concious decision to pick up that rock, bat, knife, gun etc. and actually carry out their horrific acts.
The average individual whom is raised in a stable family and is not mentally defunct does not go off the deep end. Such anger and angst is born from somewhere be it in the home or elsewhere, it is up to the parent to be their for the child and try to instill into them a sense of morals and set an example on how to handle their frustrations and problems responsibly.
Of course there are those cases where the parents did everything by the books and really did try, but each child is different and their personalities play just as big of a role. They will choose to do what they want to do regardless of what others tell them, such is the ways of free will.
There is no easy answer to this, but IMHO, blaming something like movies and video games is just a cop out to escape the responsibility for poor parenting (or not in some cases, again free will). Take responsibility, own up to your actions (or lackthereof) that's how I was raised. I just hope I can instill these beliefs into my future children someday (after I meet a woman who shares them all the same of course).