To be fair though, the person who was quoted, did not blame videogames they actually said that videogames enable psychopaths to experience their fantasies. The words have merely been twisted by both sides of the media to bring out a sensationalist headline that panders to both sides of the argument.
I would say that violent videogames do have the ability to stimulate those who have violent tendencies. It is not a single causal factor, however, it does play a part. Violent games, violent films, violence in real-life, alcohol, drugs and an underlying psychological problem all play a role. It is not just bobbins, here is a good summary of the myths and evidence:
Violent Video Games: Myths, Facts, and Unanswered Questions
It has been shown that people playing violent games, will display more aggressive behavior after finishing play. Of course this is not long term, but directly after playing your behavior is more aggressive due to the stimulation in your brain.
It is not the case that everyone has to play Animal Crossing or Harvest Moon only and we will all be safe. However, it is understandable that playing a game where you are shooting hundreds of people in all gory detail, might make someone with psychopathic tendencies more likely to go out and do it afterwards. They would in all likelihood still go and do it at some point, but it is a factor in the equation.