I think that what most are upset about is the injustice of it. If you don't put a motor on the bike, and just peddle (or even coast downhill,) the only speed limit is the same one that autos follow.
Suppose you add a small motor, though, in order to reduce gasoline consumption, and to decrease traffic congestion. Then, if you go over 20 MPH (and, from reading the law, it appears that the motor may not even have to be running...) you could be socked with a huge set of fines, (operation of an unregistered moped, an uninsured moped, and possibly, if you don't have a license, operating a motor vehicle without a license.
I agree, though, that the law should be changed using the legislative process. But, I still get worried that if I don't watch it when I'm going downhill, that I could get socked with huge fines.