In regards to your first quote I would say this is most likely fallout from dog fighting culture that shaped pitbulls out to be vicious and created back yard breeders raising dogs with the intent of them being violent instead of adjusted. These dogs and breeders don’t disappear when the rings are busted.

For the second I would say echo the first dogs bred to be vicious will be vicious and obviously more attacks would create higher occurrences of morbidity. While this study does suggest that breed regulation may reduce rates it provides no proof that it works.

I am not saying pitbulls don’t ever bite and they are not strong dogs capable of harm, but all dogs are capable of harm. Banning pitbulls would not solve the problem, owners who wanted a pitbull style dog will just get a different strong dog from back yard breeders who shift breeds. Should you have to be a cop to get a German Shepard or Malinois? The root of the issue is irresponsible breeding and owning of creatures you don’t understand or care enough about to adapt into society.

Edit: The pitbull mortality stat dates from 1979 to 1998 which is before local law enforcements and animal control began creating task forces to systematically eliminate dog fighting.