Just cos we got cameras, doesn't mean we are policemen. Doesn't mean we have to be nice to people who are doing something wrong either, lol.
What I like is that you really pissed him off. Ruined his day. He might be a really nice guy in general, but he would have been on edge all day. Not only that, he knows he is being watched and can be seen from any angle when he is unaware, so he will think twice about it again. Might not stop the same reaction, but that's only a defensive tantrum having been caught.
Surprised you didn't stop just in front of him the second time round - you know, aloingside the next car so he couldn't ram you - and wave. Nice and condescending like. Hee hee.