The breed is mythical for two reasons. One, its fabled ferocity is the stuff of legends. Two, it's a breed that doesn't exist.
You might think that even a politician would have trouble banning a non-existent breed, but don't underestimate our elected representatives. An attorney-general in full flight, such as Ontario's Michael Bryant, is capable of banning anything, whether it exists or not.
Still, why on Earth would you want to ban a breed that doesn't exist? Why, for that matter, would you want to ban one that does?
Easy. You ban a breed because it's vicious.
But wait a minute. Breeds don't bite. Individual dogs may bite, but breeds don't. Especially breeds that don't exist.
Stop being technical. Whether a breed exists or not is a piffle for pedants, like kennel clubs or veterinarians. Details can be sorted out. "If one of your four grandparents was a boxer, a Frenchie or a Patton's dog, you're outlawed as a pit bull." Why not? They did it at Nuremberg. A politician with a vision bans first and asks questions later.