Well, I'm no expert. I just figured it had to be something analogous, or they wouldn't have a ban on the little buggers.
That would be true if laws are always made for a good reason, but sadly many are not.
Like I said, every other state surrounding PA allows them and there are no wild bands of them there. Most of the domesticated breeds are African, so don't do well in cold weather.
I can't seem to find the details of how it started, but it seems the original law 20 years ago was some paranoia about importing them, so they were still legal but only if raised for a certain number of generations inside the state. Then some breeders broke that law so they went full ban.