Stereotype (v) - to form a standardized mental picture that represents an oversimplified opinion, prejudiced attitude, or uncritical judgment.
We all tend to do it, even though it's not fair.
After all, not every man in a pickup truck is a dumb redneck who thinks he owns the road. And not every woman in a giant SUV, with phone plastered to ear, is a silly twit whose severely-limited focus is anywhere but on her driving duties. (And not every middle-age guy in a shiny red Corvette has "ED issues." hahahaha)
And likewise, not every bicyclist is a clueless self-destructive jerk who thinks traffic laws apply to everybody else (not to mention the laws of physics).
I wish everybody who straddled a bike and rode in public would realize that, like it or not, he (or she) is an "ambassador" for cyclists. Other roadway users will observe his behavior and form stereotypes, either positive or negative. His behavior might result in other cyclists getting cooperation from motorists, or it might create resentment and hostility. And who knows? You might even inspire somebody to think to himself, "Hey! I could do that! I don't need to drive a car everywhere!"
Every time I see a cyclist riding against traffic (especially when other roadway users are having to take extraordinary measures to avoid running into him), or riding at night with no lights, or swerving in and out of traffic, or ignoring traffic signals as if they weren't even there... I feel considerable resentment and hostility. And even if I'm on a bike myself, I think to myself, "Look at that clueless self-destructive jerk! There sure are a lot of 'em on bicycles..."