This is true for the majority of these homicidal losers because such an exhibition would show them to be Leftwing whackos, however....
When the shooter is not Left wing, all bets are off--make him a white supremacist and then it is the Confederate flag and redneck states who are to fault (To the point that some insane Leftist rag writers suggested rekindling the War Against Southern States--known to most as the US Civil War).
Which is almost always.