High energy dogs such as the Pitbull, American Bulldog, Staffordshire Terrier, Border Collie, German Shepherd, Dachshund, etc are all breeds that needs mental stimulation and exercise.
Too many people buy these dogs thinking the muscular, atheletic nature of the animal reflects their own macho "tough" identity, such as ghetto niggers. This means they do not neuter the male dogs because they equate the testicles on the animal to their own. An unneutered animal has increased sexual frustration, additionally making them more difficult to control when hormones flare.
The typical life of a bully dog in a ghetto neighborhood is one of frustration and restraint. Shock collars, spike collars, invisible fences, 6ft fences, and long hours alone chained in the yard or inside the house doing nothing. The dogs begin to develop unhealthy habits such as barking at whatever they see, chewing to release frustration, scratching at furniture and the house, etc. Ghetto people do not take their dogs to discipline courses, dog parks, dog training, so these people don't learn how to treat unhealthy habits. The dogs are antisocial and, if raised from puppy, do not know how other dogs socialize making them an overall detriment to even dog society.
Dogs cannot rationalize the humans who go to work everyday. They don't understand why you leave them at all. A lot of dogs experience seperation anxiety when your family, their pack, leaves them alone. That's simply not how dogs work. Packs stay together all the time in the wild. Pet birds and sugar glidars will also experience anxiety when you disappear. These are all social animals who need you by their side.
So you've got a sexually frustrated untampered animal, an animal that does not get any mental stimulation, no exercise, no discipline, and they have pent-up energy. That animal will see a small squeaky creature such as a child, squirrel, or other small animal and go after them. Herding dog instincts kick in and nip at thr heels of children as they would a sheep. Bully dogs will cause the most destruction due to their strength and instinctively not designed to let go of whatever they've got a hold on.
The solution is simply thus: learn how to train your dog, exercise the animal, teach them that you will return to relieve seperation anxiety (as dogs are smart enough to be taught so). Any dog is effectively the same, the question is what we as humans allow them to get away with due to their physiological features. The equivalent of these untrained, ferocious pitbulls are chinhuahuas and other small dogs who are similarly aggressive.
We notice pitbulls due to their high population and size. We don't let pitbulls away with aggressive behavior. We let small dogs get away with aggression. Unfortunately, society has decided that pitbulls, border collies, etc are not safe dogs to keep, making them first in line to be humanely killed, when it simply is not so. City people are just all lazy niggers who don't have compassion or desire to learn about their animals.