The title of this article is misleading and simplistic. These matters are always multi-causal and more complex. As psychologist Dr Jack Fenton points out, there are many reasons why individual kids turn to violent video games in the first place. He mentions parental separation and living in an unsafe neighborhood as two. Others are social anxiety and low self-esteem and peer pressure.
The question he also raises is whether to see such over-absorption in the media as an actual clinical entity. See my article in Psychology Today for some of my ideas on this subject.
One video game maker claims that he would never sell games like Call of Duty to an 8 year-old. But he also asserts that parents are not paying close attention to what is the content of the video games their children play. Who is responsible for alerting them: the maker of the games or the culture at large?