Cursed as I am, I see both sides to this argument. Many's the time I have had to inform ignorant motorists that, no, actually I can't "just ride on the sidewalk," because that's against the law where I live also. And I have really very little patient for cyclists who do ride there.
That being said, there is a tremendous disparity between the motorist and the cyclist (you're behind the wheel of a 1000+ pound metal box - it is literally impossible for anything I do on my bike to hurt you unless I am strapped per Res Ipsa's suggestion), so I am also rather disinterested in the "cyclists don't obey the rules" complaint from motorists, with some caveats.
1) I'll admit I don't live in a major metro area, and I have noticed when I have visited places like the Loop in Chicago and basically all of Manhattan that cyclists there seem more willing to actually take their lives in their own hands.
2) Look at the statistics. If you are motorist and you strike and kill a cyclist, the chance of you facing any legal consequence (meaning so much as a traffic ticket) nationwide is about 50%. Just last year, I observed a wrongful death trial involving a father of two children who was struck by a motorist passing another vehicle on a two lane road and came over the fog line - meaning the cyclist literally had nowhere to go. The collision took place at 4 PM on a bright, sunny day in August. Not only had the local prosecutor's office declined to press any charges whatsoever, but the jury in the civil case awarded the deceased's family only token damages and found the dead cyclist (who, again, had nowhere to go) 40% negligent in causing his own death. Why? Because although he was wearing a helmet, the jury apparently felt he wasn't wearing enough high-visibility clothing. On a sunny summer afternoon. This is how cyclists are treated by the legal system every single day. So, respectfully, the anxieties of motorists aren't of much concern to me. You can literally get away with murder if you are driving a car and hit a cyclist. I'm pretty sure you're not the one who should be constantly afraid.
3) In my personal opinion, the "cyclists don't obey the rules" complaint has more to do with cultural dislike than anything substantive. Upon what do I base this opinion? I'll admit, it's anecdotal. But I'm pretty sure I'm on to something when I suggest that it's a cultural grievance, based upon the number of times idiots in cars roll down their windows to shout at me. For some reason, their comment is never "you really ought to be more careful," or something like that. It's always some variation on "get off the road, you spandex-wearing faggot." Or guys driving big diesel trucks rolling coal on me with no provocation whatsoever. I can only conclude that some people are just that triggered by my choice of hobby.
"There's no play here. There's no angle. There's no champagne room. I'm not a miracle worker, I'm a janitor. The math on this is simple; the smaller the mess, the easier it is for me to clean up." -Michael Clayton