In our quest "to blame" and to find some complicated political and social answer..., we have missed a simple truth and the heart of the matter.
A gun, with its killing-power, in the hands of an adolescent male, does the same thing to a human mind that cocaine does.
You can get the same adrenaline-rush by driving a very fast car or winning a high-dollar poker tournament.
Ultimately - nothing is as-sure or as-available as "the gun" and they begin fantasizing about using it - like a junkie chasing a more-powerful high.
That's all there is to see here.
Asking a gun-nut what we should do about gun-regulations is like asking a crackhead what we should do about cocaine.
"Cars don't kill people."
"Nukes don't kill people"
"Lets not have traffic laws and lets give everyone nukes."
The logic of a gun-nut is "the logic of a junkie." Their input is irrelevant while getting innocent people dead.
I am absolutely sure that this mass-killing was nothing more than "the ultimate adrenaline-rush for a power-junkie."
And that's all there is to it.