I feel you are on to something. I think that on top of those other things, the last straw is that the U.S. society is much less integrated. My neighbors have said 3 words to me the last 10 years I lived here (moved from Europe). Where I come from the whole town would know the troubled kid, would either step in before the bullying got really bad, or sure as heck would not let the kid buy a machine gun.

Maybe the problem with the US is that the society is just too free. Or not enough churchgoing.