Often dogs are trained to fight and attack. Pitbulls have a bad reputation rooted in bad human behavior; it's not the breed's fault. The behavior of a few Pitbulls doesn't mean that the breed is inherently vicious. Instead it means that their humans are assholes. I've personally met many Pitbulls who were just big mushpots of love.
American Bulldog Mix Dog for adoption in New York, New York - Brutus was left behind & abandoned by his previous "owners" treated like he didn't matter & left to fend on his own. He was viciously attacked by neighborhood dogs & suffered deep lacerations to his face. Rescue Dogs Rock where he is now recovering describe him as very sweet good with people & despite his injuries good with other dogs.