*snort* Crime in general has always been fueled by social and cultural factors much more so than anything else, and these particular types of crimes are directly related to how we deal with and view mental health in this country.
Human nature does want the simple solution and in out culture, that means blaming the object (guns, alcohol, drugs, art, media) rather than the core issue which is much more complex and much more difficult to rein in.
The truth of the matter is that there is no ultimate solution and the things we can actually do require a lot more than just banning something.