Freedom costs.
I think that EMN has it right; not only is trading liberty for safety morally wrong, but it has been shown to be counter-effective. I know plenty of people living with autism, some functional adults in society, some needing the lifelong care of society. None of them have ever committed mass murder.
We will never, ever be able to eliminate crazy people. In fact, most of the brilliant scientists, entertainers, athletes, and others who are "special" examples of humanity have a little element of nuttiness. That is generally WHY they are able to think, act, or perform past the normal limits to which most of us are constrained. Thus, I really don't care to TRY to totally eliminate "crazy". That said, we all need access to the tools that will protect us from Mr. (or Ms.) Mass Murderer. There will ALWAYS be a tool for the effective elimination of large numbers of people if you take guns away from the law abiding; there just won't be an effective tool to resist these attacks.
Firearms are the ultimate in equality: A gun doesn't care if you are black, white, asian, or latino. It doesn't care if you are a 280lb man, or a 102 lb woman. Gay, straight, bi, transgendered. Christian, Muslim, Jew, or Pagan, Firearms are the ULTIMATE in equality. They are the tools that prevent simple Might is Right rule.
Sorry, getting worked up on the ole' soapbox.