Disgusting. Why does this shit only happen in America? It happens every few months.
Well, besides the easy access to guns, the aspect of American society that stands out when compared to most other western societies is the lack of family structure. Not just divorce rates but the fact that children around the age of 16 gain a sort of independence that they don't get elsewhere and, even leading up to those years, families seem to be constantly changing. Lots of individuals get completely marginalized and are left to their own decaying presence. Another unique aspect of American society is a desensitization to violence, for example how it's OK to show someone getting shot at close range in the face on daytime television. 30 - 40 years ago these trends hadn't developed yet and outbreaks like this happened much less frequently.
Not trying to piss all over this country, it's hard enough explaining this stuff to people who don't live here.