I agree with almost all of what you posted here. The only place I have a little issue with what you wrote is on the subject of metal detectors in schools. I don't disagree that schools should have and use them (these days, we have to do everything possible to protect students and faculty), but the majority of the responsibility ALWAYS has to be put on the parents in these cases. Every security system makes an occasional error. If your kid doesn't have access to your gun, they can't bring it to school in the first place.
The blame should be put on the mother, and she should be held responsible to the fullest exstent of the law.
There have been hundreds of studies done on the psyches of kids and how they develop, and most of the credible ones indicate NURTURE over NATURE (with a few exceptions) as the most profound factor in a child's psychological/emotional development. How a child is raised/taught/treated by those closest to them--along with traumatic events they experience throughout their youth--is key to determining their psychological and emotional health.
The average sociopath is created to be that way by the people and environment around them.
That being said, some people are born with, or develop, neurological disorders that make them predisposed to sociopathic behavior. Brain chemistry trumps everything...