it was only a matter of time before suicidal libs decided to start taking officials down with them. like it observably works for the right so why not the center? they don't have theory to explain why it doesn't work - just moralizing about how violence is bad that doesn't hold up when you realize it can be justified as self- or community-defense.
Per the story, he did phone it in to warn the police he was coming. And then he showed up and immediately got arrested.