It was refreshing opening up the thread and seeing this comment first up. I wasn't actually aware that the cyclist had a history of provocative behaviour, but it doesn't surprise me in the least. Don't get me wrong; the driver in this case was 100% in the wrong, and a psychotic dickhead, there's no debating that.
But what I find equally ridiculous is the behaviour of cyclists like this guy. Yes, bad/aggressive/oblivious drivers are scary, especially if you're a cyclist. But if you're going to initiate a confrontation following a close call by smacking someone's car, then you should be prepared to negotiate any ensuing confrontation with the same confidence.
Don't want to deal with an overly aggressive manchild? Don't smack the car. Smack the car? Don't go from incredulously shouting "are you fucking serious bro" to "please calm down sir" and "please step away from my property sir" (wouldn't want anyone to touch your property huh?) in under ten seconds flat.
That's not to say I don't understand why a cyclist would smack a car in this situation; I get it. I understand the frustration, the danger, and the fear. That doesn't mean it's a bright idea. We don't live in a perfect world full of perfect people who act rationally all the time. If you smack someone's car, even as a fair warning that they're driving like a prick, you have to understand that you're living in the real world where people don't like having their car's smacked, regardless of context. You have to expect that your action could likely escalate the situation.
It's a lot harder to attribute complete innocence to a party when they're essentially the one who initiated the confrontation, and then promptly fumbled to back out of it when it was more confronting than they'd anticipated. That's a bitch move, 'justified' or not. Best course of action? Yell something that makes you feel better and move on. Failing that, be prepared to back your choices up.