I’d add that the last layer these #guns apply is the "justifications" layer, the "reason" they are committing the act. In the same sentence the Pulse shooter referenced three completely different groups in the Middle East that have been at war with each other for a long time  An Islamic scholar he was not. We always get hold onto the wrong piece in explaining these things, the "why."   That’s just the shooter rationalizing. Whether KKK, White Supremacist, Black Separatist, Christian Identity, III%, or pledging loyalty to some Middle East group, at heart these are: 1. Grudge collectors (real & imagined) 2. Failed Or disappointed people - professionally, personally, educationally with relationships 3. Psychologically unbalanced 4. Are driven to make their "mark" in the world, to prove our judgement/rejection  of them wrong 5. Involved with the American gun fetish 6. Only then do they add the psychological justification of a "cause." They pick the justification just like you’d choose a coat from a closet. I can’t find any examples that don’t touch on at least 5 of 6 of these.