Lots of people are falling all over themselves to disclaim any blame for inspiring Mr. Holmes's actions. In large part this has to be correct, because the fact is that millions of people play First-person-shooter, or "murder simulator" video games, and yet almost none of these players become actual murderers. However, when it is discovered that Jared Loughtner, or James Holmes, or the Columbine kids liked to play violent video games, some m0r*ns start screaming that the video games caused it. They appear to have got the causality reversed. People with violent tendencies will surely be attracted to violent video games, but the games didn't make them that way in such cases.
Others say that Hollywood's ultra-violent John Woo style "action movies" that glorify guns is responsible. Again, it's clear that hundreds of millions of people watch these movies and do not become violent. They clearly do not CAUSE it.
However, they certainly do make people numb to it. Also, while violent movies and video games do not cause MOST people to become homicidal maniacs, people who are already very emotionally disturbed to begin with may only need a little extra push.
It is in that vein that I feel it necessary to point out that the "Dark Knight Rises" had a trailer called "Gangster Squad" that depicted a shooting IN A MOVIE theater. Many people are not even aware of this, since Warner Brothers quickly pulled the trailer in the wake of the news. I remember seeing the original trailers in the movie theaters months before the movie came out. A number of people expressed discomfort at this time and some in the media did even warn that such trailers might lead to copy cat behavior. It is hard to avoid the possibility that Mr. Holmes may well have been inspired to copy cat the trailer, just as at least three other unstable individuals have been inspired to copy cat threats of violence against movie theaters in the couple of days since Holmes's attack.