Although I don't agree with the idea of banning a specific breed of dog, or for that matter, of banning most "exotics" (that's based largely on my position that "banning things" is a damn stupid idea!), I do think there are animals that shouldn't be as readily available as they are.
A few years ago, I walked into an Appleton, Wisconsin pet store. We're not unfamiliar with herpetology, and, in fact, are very interested in procuring a ball python at some time in the future.
As I looked at the reptile cages, I spotted a Nile Monitor.
Now, I think monitors are beautiful, fascinating creatures and wouldn't mind owning one if I had the proper enclosures and resources to ensure the animal a proper and humane existence. That's the same standard I apply to ANY animal.
But here in front of me was a nile monitor ready for anyone who could plunk down the cash to purchase.
Having recently watched the tragic deterioration of two iguanas a friend of mine had purchased without bothering to gather proper information on raising iguanas, I was appalled. Most animals such as this are bought on a whim, for the "cool factor". I have known owners of such diverse animals as gaboon vipers (venomous, very dangerous...NOT for the inexperienced), reticulated pythons (beautiful, and very dangerous, though nonvenomous), and alligators (I don't think I need to elaborate on the potential dangers here). Among those, MOST have been responsible owner. But all it takes is one irresponsible owner and a dead child or pet to give the responsible owners a bad name.
So if you're thinking of purchasing a potentially dangerous animal, fine. But PLEASE do your research first.