Can’t speak for Animals, the human kind, have done to the breed but here is some info:
http://dcentric.wamu.org/2011/02/pit-bulls-from-americas-dog-to-public-enemy/
I don’t defend the dogs that did this, but the entire breed should not be condemned.
They are actually peaceful misunderstood puppy wuppy dogs - the Muslims of the dog world.
I don't condemn the breed, but I do recognize that they were originally bred to have the aggressive hunter killer instincts most of them exhibit.
In my view the so-called Pit Bull terrier is an exotic breed of animal that is only marginally suitable for ordinary domestic ownership. I'm of the opinion that they should be kept in the same way that people keep other dangerous animals, that is, under strict regulatory guidelines, permitting, kenneling, etc.
They did everything wrong, right out of the gate.
Four weeks old is -too young-, no matter the breed and they created monsters with littermate syndrome.
The dogs will *always* be “us against you”.
Stupid owners.
A breed is not a living animal. It is perfectly safe and reasonable to conclude that the breed is genetically defective, and terminate it by simply neutering all the present dogs that are part of that breed. You don't need to kill the dogs, unless they ask for it. Just don't make more of them. Dogs' lifespan is short enough, and dogs are not going to worry about the future of their breed. Even humans largely don't worry about their own species...
Otherwise one would be able to ask a perfectly valid question: how many human children would a proponent of the breed be willing to feed to the dogs, just to keep a certain set of angry genes around? Is the breed valuable in some unique way, outside of dogfighting? What does the humanity gain from this breed? (It's already obvious what it is losing.)