While I tend to share your wonder at the arrogance of some of these freaks, I think it's more of a "These suckers never showed me any respect, so I'm gunna off myself just to show 'em. But because I hate 'em so much for all the disrespect, I'm gunna take a bunch of 'em with me." It is still fatally flawed (excuse the pun) logic, but hey, if you're talking about a nut case, logic doesn't play a big part. It strikes me that this is another rather strong argument for CCW. When a nut case draws a weapon, everyone of his nearby co-workers out to draw down. It's sort of an extrapolation of the old concept: People are really polite at gun shows.
I remember my first trip to the Knob Creek MG shoot. ...Folks walking around with side arms everywhere, Full Auto weapons on the line and out if rental areas, long guns over shoulders. There was a pickup truck with what looked like a dual AA gun mount in the bed driving around the range and nearby roads.
Everyone smiling, saying hello, no pushing, shoving jostling and for sure no line cutting. An accidental bump got a casual apology. I think they was generally cause gun folks are just better....but if anyone was having a bad day, they were mindful of keeping it to themselves....
Haven't been here in a few years...making myself homesick..