Don't worry I see plenty of bone headed driving too while I'm on the road whether it be by bike or car. The thing is, when you get stuck in traffic with a car you will encounter a lot more bicycles than cars because if you're in no rush, then chances are, you'll be stuck between the same two cars in front and back. Which thereby limits how many cars you will encounter to the persons in front, behind and coming in the opposite direction.

I find that most people who throw it into reverse near an intersection or at it, don't even look backwards, or check in all directions before doing so. There are definately some motorists who should not be on the road. But some just have a temporary lapse in judgement.
Bad judgement/stupid people exist in all sorts of fields.

I ride like I drive. Observing traffic flow, positioning myself to avoid hazards, constantly on guard for some dangerous stunts some people like to pull. It's not inconvinent to do so for me, at most it would add 2min to my ride. Impatient people want to get there faster, but often times are short sighted, so they either speed or run the light and get stuck at the next red light behind another car anyways.
If you run the light and get hit, you figure it's only your butt who gets hurt. Such a death wish states that you don't care what kind of carnage or chaos you will leave in your wake. Traffic becomes backed up for miles, you damaged someone's car, etc. etc. It's an inconvinence to others because you are the center of the universe.
I enjoy riding on my bike, but I'm not a daredevil. I'd rather not injure or damage someone else simply because it's convenient for me.

Most people won't change their habits until something happens to them, they witnessed something or something bad happens to their immediate associates. Some education courses would be nice for many motorists and bicyclists alike.