I hear this kind of crap all the time and really it is mind boggling. Do you know that car that cut me off yesterday, well did he give all cars a bad name? Do you know that the police have all whole traffic sections dedicated to bad car and truck drivers, at least they do in my city. They even have red light cameras and photo radar for vehicles that break the law. But nowhere do I see vehicles getting a bad name because of these infractions. Go to traffic court, you will see thousands of people trying to fight their "mistakes" in court. Somehow vehicles don't have "bad names".
I will admit there are bad cyclists but guess what that number is tenfold when it comes to motorized vehicles on the road. I see bad drivers every few minutes. And I really don't think they are ruining for the rest of them.
And I love these holier than thou cyclists because we all break the law. Some infractions smaller than others but none the less infractions. I have yet to meet a cyclist that follow all the rules of the road. Then again maybe you are one perfect cyclist.
And for the cyclist that will no doubt blow past the stop sign this morning without even looking, someday Darwin's Theory will catch up and we won't even need to have a discussion.