Guns don't kill people, they just make it oh so much easier. We must stop seeing guns as tools to solve problems. The troubled souls see our gun culture promoting weapons that so easily kill as problem-solving tools - including arming for self-defense. Some even see these violent tools as a way to prevent such tragedies. "If only the teachers were armed!" maybe students? Kindergartners?
The problems of the mentally disturbed are not the same as those of most of the sane people. When it's them against the world, they choose the easiest tools in their horrific attempts to take on the world. They always lose which is an inevitable part of the plan. But not before they cause more hurt than they could have ever possibly suffered.
I've written about these themes before, including the silly spoon analogy. There is not much more to say. One guy said it pretty well today:
An easy link to the post at By Common Consent that Papa D recommends below.