I've owned many types of dogs including a Pit X and I have known many people who have owned pure bred Pits, never have I seen one act aggressive towards a person. Pits were bred to fight other dogs but they were also bred to love their owners. A friend of mine who is a police officer and a Pit owner has told me that the police can't use pits as police dogs because of their reluctance to attack or bite people. Pits are also never used as personal protection dogs for the same reason, they would rather lick a thief to death than actually attack them.
These dogs that are shown on news reports for attacking people are almost always mistreated and improperly kept. Any dog regardless of breed is a risk to attack if they are kept chained 24 hours a day, abused and in many cases starved. I agree that pits can be very dangerous dogs if they fall into the above situation because of their power and bite strength, but I also believe that in most cases it is the irresponsible owners who should be punished not the dogs.