Personally I believe that red light timings should be more about personal safety than revenue. I'm just saying that I can't imagine a legal argument for federal regulation which the OP suggests.
Also, on your second to last statement (racial assumptions aside): do you really believe that criminals will stop being criminals if we only just accept them? Isn't socially deviant behavior the reason why criminals get pushed out of society?
So certainly they will want to try it before they buy it. But if they like it and their friends like it, they will likely buy it if they can afford it.
Just like how only people who truly need it will take welfare. It has nothing to do with the fact that many people feel that they deserve to get "free" stuff just for being born.
The real criminals sadly don't get caught because they are harder to catch.
That's why we have a "legal system" not a "justice system".