The problem is that some nasty bastards got 'pit bulls' as a status symbol. Some bought them to guard their drug houses.
The ones I have met which were raised by families and were from something other than a puppy mill were kind and gentle, well behaved dogs.
A lot depends on the owner and the breeding, which traits are emphasized by the latter and how they are raised (It's a combination of nature and nurture).
Similarly, there have been people who will kill and eat their date for the evening, we have people who rape children, who engineer and implement programs for the systematic enslavement, torture and execution of millions.
It isn't the breed so much as how they are raised.
That said, some just aren't wired right, and I think that's at least partly a result of inbreeding by people who want viciousness to exploit. It's the vicious ones that make a bad name for the others, just like any group.
