I'm just going to say it because it becomes most blatant in cases like this, but the "authorities" never move so fast and work so hard to find and stop someone who targets them.
I agree, this guy was unhinged, obviously. Planned and put some relatively large resources into assassinating political opposition. I suspect right wing, target list is pretty telling, the flyers being a diversion for motive maybe thinking he might get away and that would draw suspicion away from a right winger if left at the scene, just my guess. Could be religious based, though I don't recall Jesus telling you to go and kill people, but clearly the guy started down this path a while ago and his family probably knew.
In the big picture when govt becomes this powerful, it is a defacto religion, especially to those who believe its the answer to everything, the lefts reaction to losing the power of it is the most telling of that. People persecuted for opposing and resisting and is some cases even questioning, its not all that surprising other religious zealots would go to war with it. Wouldn't surprise me if he expected to kick off a revolution with his acts.