I'm not smart enough to understand this but I'm 45 and when I was coming up plenty of people had guns but they didn't shoot up schools. Something has clearly fundamentally changed
I had the same thought. Here is an idea. Political media's lies and polemics almost exclusively of the right provides the hate. Movies and first person shooter games have numbed kids to consequences of the anger they express.
Who knows what is going on at home to junior when daddy is watching Fox news and drinking a case of Schlitz 16 oz and shouting at mommy and the kid locks himself in his room playing videos all hours.
KIds can be cruel to each other. 1 plus 1 plus 1 =mass murder at school.

