I don't disagree that the present regulation is not particularly effective. Perhaps I did not choose my words well, but I think I've stated this issue well enough. Either the government has the authority to regulate or they don't. I'm inclined to say they indeed have a reasonable claim to be permitted to write regulations that cover these devices.
Note, they have not actually banned ownership. They have only created a system where it's not simple to obtain certain devices. While I'll also agree than in principle it's better to deal with a problem by punishing wrongdoers than it is trying to regulate a object, sometimes you are going to need a layered approach. In your example of a 600hp car, try getting a license issued to your F1 McLaren. A ban on private ownership of large quantities of pure U-235 seems pretty reasonable. Mass murder is already illegal, but I'm not sure that is enough to deal with your having a nuclear device in your garage.
It would seem that our single point of disagreement is just what power level of laser should be readily available. The prior rules that had a complete prohibition on any IR power level were certainly too restrictive. The current power levels don't seem unreasonable to me. If we agree that even LE has no practical use for a 25mw pointer, what's the problem? You have some unique requirement for it, build one, no one is stopping you.
It seems that the regulations have at least some effect, since people constantly complain they don't have one and can't get one. Since there are pretty reasonable substitutes, like LED's, what's the big deal about not getting a nice new PEQ-15? Perhaps not all of them are stolen, but the individuals that bought them on letterhead and then sold them are at least in breach of the sales agreement they signed, the devices are not 'legitimate' as far as the factory is concerned. I'm not going to advocate you buy an orphan device, and you pretty much don't have any way to tell it's NOT stolen.
So, it appears we only actually disagree on the amount of regulation, and the form that is 'reasonable'. That's a matter of opinion. We agree to disagree, I think what is currently in place is fine, you don't. It is, however the law. Don't like it? Get it changed. End of thread for me, but it's been interesting.