Well, I think it all boils down to an American culture of "I'll do what I want, everyone else be damned." For some reason Americans have an image that the road is the "open road" from old movies where people can do whatever they want relatively consequence free. Certainly no one is perfect, but enforcement doesn't have to mean ticketing someone going 1km over, and I don't think it would, since there certainly have to be built in variances for speedometer differences, random changes, etc etc. I know here in japan I can go through the automated ticketing machines on the highway at 20km over the speed limit and never get a ticket, because they're only there to remind people to slow down and to punish heinously dangerous speeders.
Seems like a perfectly reasonable and good system to me.
You should also keep in mind that Americans have a relative high degree of freedom with what they can do with their cars. Here all cars that can go any amount of fast come with built in governors from the factory to prevent the owners from ever using that speed.
Anyway, while I agree that there is certainly a wrong way to approach the situation, the typical American approach of fear-mongering seems pretty silly. I mean, you get the conservatives complaining about government tyranny over traffic cameras on the one hand and then trumpeting the patriot act as a necessary measure for "safety" on the other.
