Breed banning is so stupid! But dogfighting is even worse I think. as micki76 said, it's probably to prevent dogfighting. It's horrible that it has to come to that though - I'm sure there are other ways to stop dogfighting!

Oh and look at this law, from the link Toller 42 posted:

"City of Vaughn also automatically considers Staffordshire Bull Terriers and American Staffordshire Terriers to be aggressive UNLESS they are registered with either the Canadian or American Kennel Clubs."

what?! so regestering them makes them non-aggressive?