Sure you have bad breeders. You also have a breed which has been bred for fighting for several hundred years.
No. You don't have a breed. At a minimum, you have three breeds, and if you used only those three breeds, then you don't end up with all of the 'pit bull' deaths each year. Deaths by bullmastiffs, bullmassadors (bullmastiff/labrador retriever mixes), American bulldogs, American bullies, Alapaha true blue bulldogs, unknown mixed breeds, Cane Corsos, Presa Canarios, and other breeds are first credited by police or the media as pit bulls and corrected later.
Try these two tests:
All of the dogs shown are purebred breeds and the American Staffordshire Terrier and Staffordshire Terrier are not shown, although those two breeds most resemble the American Pit Bull Terrier and are considered 'pit bulls.' In one of these test, 72% of people who take the take can't identify the American Pit Bull Terrier, although the photo is a prototypical photo of an American Pit Bull Terrier.
You can see why these other breeds can be misidentified as 'pit bulls.' Many of these dogs are also fighting or protection dogs and can be dangerous.
This is the problem with breed-specific legislation. We have a 'pit bull' problem in the U.S. that involves more than pit bulls.