The pit bull problem

An article at the BBC explains how pit bulls, popular as guard dogs (and fighting dogs) in South Africa, are facing a strong public backlash over their propensity to attack and kill children.   

I have always been a complete skeptic with respect to the "it's how your raise them" defenders, regardless of whether they are the public, vets, or from the RSPCA:

"The defence by pit bull lovers that it is how you raise the dog does not hold water. So many people, including joggers have been attacked and killed by pit bulls," says the petition, which has more than 129,000 signatures so far. 

When you go to a dog park often (as I do) and see things like a young collie's innate inclination to start playing with smaller dogs in a "round them up like sheep" sort of way, I don't understand why certain people think a bred can't have an inclination to attack small humans at the slightest deemed provocation.