As a sometimes bike commuter, the story of the bike messenger that stalked and then attacked a guy he had a run-in with hit home a bit. Most cyclists will regale you with hours of stories about jackasses in cars that seem to be disproportionately middle aged white guys in Dodges. They cut you off, they throw things, they get out of the car until they realize you are bigger, have pepper spray, and in a hell of a lot better shape (ed…excuse me–well normally I am). They then usually quickly get back in after a hard stare.
But cyclists behave badly quite often as well. Some have trailer for bikes to bring in heavy stuff that may be dangerous when dropped on the road. There are of course the riding examples of Darwinian Natural Selection who ride against traffic despite clear guidelines in the laws of physics, but ultimately they are mainly dangers to themselves. Others can be quite horrific such as the bike messenger.
Zorn then uses it as a stepping stone to discuss forgiveness in a quite touching article.