Watching that video coldly, from a desk, I would agree with everyone who says he should have let it go. But having been in the real life situation more times than I would wish, I know that's it's completely different on the road, with the memory of what you worried might have been your last moments fresh in your mind, and adrenal coursing through your veins, that it's hard to behave like homo economicus, doing exactly the right thing for your long term survival. But even from my desk, he didn't over do it, just one zinging "knob" as the cab went by. Yeah, not ideal, but nothing to suggest he was deserving of being waylaid down the road.
The cyclist was not pursuing the cab down that road. He would not have caught up with him. The cab driver lay in wait. It is sinister and deeply disturbing. The cab driver never felt his life imperilled, so hasn't the same excuse as the poor cyclist.
Edit: mods, do as you will with this.