I'd automatically not like him. And if he slipped up once in anyway near me, I'd feel justified to act on violence. But if he did nothing in my presence and I know (of course I'd never know for sure, but for sake of argument) he didn't do anything to anyone else that resembled what he thinks about, and only continued to write what he does and vent his issues on the internet, I'll pay him no mind.
One day he might snap, but until then, fuming over his earthly presence is just futile. Don't waste the energy in your fingers to talk about him. While I can't say for sure whether or not he's just trying to freak people out, I know it spurs him on to want to explain himself. Eventually that breeches a new level that involves him PROVING himself.
And I don't think we want that.