What trab fails to realize is that while he is indeed correct that pit bulls were bred to fight dogs, and this is indeed a linebred trait that is there, but can be controlled and nullified with socialization, pit bulls were also bred for extreme loyalty to humans. any fighting dogs who showed aggression towards the owners or "cut-men" back in the day when the breed was being molded were destroyed as it was not a desireable trait. Any pit expert, will tell you that the american pit bull terrier is the one dog that has been bred for temperment and personality and not appearance. A well bred american pit bull terrier will never show human aggression, nor will they ever be the dogs you hear about in the news. the problem lies with bad owners, image and bad breeding, its a dagerous mixture and can lead to a situation such as the one described in the story, although the story itself doesn't really make any sense. take your average ghetto thug or white trash who wants a pit. can he afford a pure bred, breed standard pit bull? No, he's spent that money on rims and meth. So he goes to the guy a couple blocks or trailer parks away who has a litter of pups, which came from two dogs who were poorly bred, which came from a pit with a little presa or a little cane corso mixed in, which each came from inbred dogs, and each came from a bad owner which came from a bad upbringing, but hey, they can sell a bunch of pit pups and make a lot of money!!
But back to negro joe and jimmy trailer; who want their pits to look tough and provide an air of strength about them. they haven't had dogs before, but they want a pit because a pit provides an image that they want to convey. But they get a little tired of taking care of a puppy cuz they also want more rims, grills, crack and meth... and they aren't the best people in the first place so they neglect the dogs, maybe let them wander free or just chain them up. The dogs aren't socialized, aren't trained, are hungry, are lonely and depressed and eventually become a bit apprehensive of humans. At this point we have the state of many pit bulls in america, which really can't be classified as pit bulls anymore, more aptly they are "image bulls." But they still have traits of pit bulls, such as tenacity, strong jaws and athletic prowess. Do i believe each of these dogs is an inhererent danger to the world? probably not, but i don't think they are anywhere near as dependable as a well bred american pit bull terrier. There are certain conistencies that dogs need in their lives to become members of society, which if you own a dog, you need to prepare a dog for the real world. At this point though, you have many dogs out there with short hair and a big head, called pit bulls, doing things completely misrepresentative of the breed, such as the situation above, even though that story seems suspicious to say the least.
Pit bulls are the most abused and most exploited breed in the world essentially, and that is how we have arrived at the situation of the breed we have today. That might be the simple explanation you need.