I don't know what makes a person get a gun and go shoot people they don't know. I've covered many of these crimes over decades in the news business. I've seen the patterns over and over again.
For reasons we rarely understand, a person goes down a rabbit hole of confusion, paranoia, jealousy, suspicion, fury – take your pick. Then he (it's almost always a guy) gets a weapon, throws together a haphazard plan and shatters the world of peaceful citizens.
Is it pure evil? Is it insanity? Is it some combination of the two or something else altogether? Of course we have a debate about guns and security and healthcare policy. Of course we settle nothing.
And when the violence cuts along social lines – when victims are targeted for their religion, race or political views – we ask if something much bigger is involved. Are we helping spur these shooters to action with the anger of our own words against "others"? Is the bitterness of our public discourse creating a jumping-off platform for lone militants in the same sense that an angry mob of many makes it easier for one person to throw a brick?
Like I said at the start, I don't know. But I suspect when a desperate person is growing steadily more hell-bent on one of these dreadful attacks, hearing the rest of us shouting probably doesn't help.