It's no different than the generalizations many people make about other subsets of our culture. Stereotypes are no more true about "cyclists" than they are about any other group. Sure there are some cyclists (spandex clad or not) who are arrogant arses, think they own the road, don't think the rules apply to them, and could care less about respect and courtesy toward others. There are also numerous cyclists who are responsible, polite, law abiding citizens of good character. The same could be said about pedestrians, commuters, truckers, bikers, and so-on ad infinitum. Anytime you hear that "all" of some group share a common negative attribute, you are hearing prejudice not facts.
"Sure I'm prejudiced, I hate bigots!"
"He's not prejudice, he hates everyone."
All In the Family, TV Series