2 reasons. #1 the pit is king of the cage #2 and most importantly, the pit has been evolved into another breed, a designer dog so to speak. Bred more for looks, than anything else. Crossing other breeds into it to make it bigger, has introduced other charector traits. Technically its a different breed. But pit has old school name recognition and sounds scary. Adding human aggression genes(mastiff) into a game dog. That in the hands of an irresponsible idiot is a recipe for disaster period.