I don't know the legislative history, but I would imagine that part of the intent was to lower the temptation exposure. If I was a habitual drunk driver, then society is probably better off if I do not live next to a liquor store. That kind of thing. Of course these laws can be politically motivated, and guarantee nothing, but they MAY be better than nothing. I would be interested to see a relevant study.
500 feet. That's about 1/10h of a mile. In my neighborhood that would probably cover about half a dozen homes.
A law like that is just a "do something" law which effectively does nothing, but makes the politicians feel good about themselves and gives a false sense to the public that something was done.
The same idiots that passed that law probably passed a bunch of other laws that makes it easy for child predators to evade detection by law enforcement or by concerned parents.
Frankly I think we need a constitutional amendment that states that any legislature that enacts a law must simultaneously repeal an existing law or laws containing the same number of words. So if they pass a law saying sex offenders must live 500 feet from a school, they need to repeal the law that prohibits high school kids from smoking in the restrooms. (Of course the only reason any of us ever did that was because it was illegal, which means that legalizing it would probably go further to stop the practice than keeping it illegal) :-)