Ok, I'm getting old. I wrote all the above but forgot what I really wanted to post, which is a link a cyclist posted on said FB page:
http://www.slate.com/articles/health...o_wheels_.html

It has a couple of really good points. Like why "cyclists" get treated as a group, but "drivers" don't. It drives me crazy. If I've had an encounter with some crazy driver I've stopped telling people at work, except the ones I know cycle themselves. It always devolves into headshaking and ranting over "cyclists".

This really flummoxes me. I know there are dumb cyclists out there, I see them every day. But I see just as many dumb drivers. They run red lights, don't yield, they honk and are obnoxious. Dumb behaviour is equally distributed, because people are dumb. Everyone does dumb stuff sometimes. Do drivers really not notice other dumb drivers? Or do they realize that that's the sort of dumb stuff they could do themselves, and therefore excusable?