Oh, I have so much to say on this topic and not nearly enough energy to say it.
1. Our society keeps looking for quick band aid solutions for a very complex problem. Violence in our country is rampant. At some point along the line, we stopped respecting one another as valuable human beings. Sure, we all like our little groups, but the diversity of the American Population is what makes it great. We must begin teaching our younger generations that respect is important. That goes for positions of authority as well as those who are less fortunate than ourselves.
2. Entitlement. At some point, people started to believe that their own wants and desires were more important than the rights of others. It appears that the younger generations do not know how to tolerate loss, rejection, or disappointment. (I blame no longer keeping score in T-Ball and teaching our kids how to win or lose with grace, but that is another topic for another day) When these young folks, usually male, are rejected or suffer some other narcissistic injury, they do not know how to deal with the emotions and therefore begin to identify some scapegoat for their intense feelings. They then begin to ruminate obsessively over it until they snap. We must help people learn to handle frustrations in a way that does not trample the rights of others. The world owes us nothing, anything we get is what we have earned.
3. Deinstitutionalisation has not been very good for America. I work daily with the mentally ill and have found that they often are unable to get services until they have done something that violates the law. At that point they are court ordered to treatment, but it is often too late to prevent tragedy. It would be interesting to have people on this forum from each state to look into the waiting list for patients needing forensic psychiatric beds. I think it would be as staggering in most states as it is in mine. Getting early and effective mental health intervention could go a long way toward preventing numerous violent acts, mass casualty events, domestic violence, and suicides.
Obviously these are just MOO. I don't think we, as a society, can get away with just blaming the means by which people carry out these tragic acts. If we want to make meaningful change we must look at ourselves and see how we have had a part in the problem and then take the necessary steps to admit those failings and correct them.