This has been bothering me for a while now and I doubt that I'll be able to get it into words adequately, but I'm gonna try anyway.
When are we going to come to the realization that we cannot hope to predict, let alone stop every random act of violence before somebody gets hurt?
Are we going to now lock up everyone who shows the slightest sign of being mentally, a little off? Or, drug them until they're so stupid all they can do is drool on their shirts? How many lives will be ruined for no good reason on account of this? And the bigger question is, who decides who is dangerous and who is not? The gov't? How long before just disagreeing with this person or panel/agency gets you a little trip to the rest home?
The real world has never been a safe place and it never will be. There are bad people out there. Some are openly bad and some turn bad at unpredictable times. The best we can do is realize and accept that sometimes all the precautions, security systems, locked doors, cameras, etc. just aren't enough and there may come a time we are going to be faced with the ultimate dilemma, the police aren't coming, either man up and defend yourself and those you care about, or die. We cannot hope to to prevail in these situations without being armed. We can't afford to stand a cop on every corner. We have to accept that ultimately our safety is our responsibility, prepare accordingly and not let some progressive bed-wetter make believe we will be safe in his "Gun Free Zone".