I was raised around Pitbulls and Rotties. Best dogs in the world to have as pets.
The reason why Pitbulls got a bad rap is because in the early '80's the media over hyped one story of a Pitbull attacking a baby. After that it was just a waterfall of story after story. Next was the Rottweiler but never got the fame the Pitbull did. Before the Pitbull, it was the Doberman Pinscher. I was there as a child! It still annoys me to this day that people can be so "brainwashed" over what they hear on TV and/or the newspaper.
Pitbulls were bred to hunt down wild pigs. It is in their blood to attack a wild pig size target.
If the Pitbull (like any other dog) is treated well, statistically it will be a good dog. However, if you beat it or train it to attack, of course it will attack.
More people need to educate themselves before yelling, "the sky is falling".