Why is video games not given behavior problem

A video game is a form of fictitious media like a book, TV-show or a Movie. Although they can put ideas or spark interest in someone, they can not change a person to the extent needed to cause behavior problems.
If you give a child a knife they might hurt themselves or others because they don't know how dangerous it is to play with knifes; They do not start mass-murdering people because they saw it on TV, even though they do not want to.
A person whom get manipulated by a piece of media is not doing it because the media is the only thing influencing them. Such a person would have to be in a specific stat of mind of their actions and might have a problem telling reality from fiction. These people have the possibility to do horrible things no matter where they get the ideas from, be it a game, TV-Show, movie, book or some other form of art.