I agree that drivers have a larger impact for breaking that law than cyclists simply due to the far larger number of them. The size and speed differences matter

I agree that drivers have a larger impact for breaking that law than cyclists simply due to the far larger number of them. The size and speed differences matter too. As far as I'm an tell about the same fraction of drivers and cyclists break the law. They, however, tend to break different laws: rolling through stop signs is more common for cyclists, whereas speeding is more common for drivers. Often when I point this out a driver decides to defend speeding, which I think is the wrong response. If the problem they claim to have is respect for the rules of the road, then justifying speeding is hypocritical. (For what it's worth I follow the law to the letter.) Plus, as you've said, the actions of a few bad people in a group should not strongly color perceptions of the entire group.