Liberty comes at a price, we know that.
We cannot presume to stop every evil and avoid creating the worse evil of tyranny over Liberty; which eventually slides down the slippery slope of one tyranny added to another until nothing exists out of our Liberty but only because it squares with some government edict, and absolutely anything can be verboten by government edict.
It is not the lack of human laws allows in evil. It is the lack of G-d in a human heart.
Very good comment.
This guy had a LOT of resources. Luckily, he, while somewhat cunning, was not smart enough to create a much larger massacre, one that would not have required a stash of firearms in a hotel room.