Statistically, people are bitten more frequently by small dogs than by large ones, but incidents never reach the media because of the small amount of damage. No legislature is drafting laws to ban the ownership of Chihuahuas. The problem lies with the people breeding, owning, or training dogs for purposes for which were not intended. Pit Bulls and their kin were designed and bred to fight each other, not people. Due to the tenacity and physicality of the Bull and Terrier breeds, people have decided to make them one of the primary representations of a bad dog.
People use the dog to compensate for their own insecurity and to promote a macho image.
These people and their dogs should be avoided. The wise buyer avoids these dogs at all costs. Those who want protection should get a breed specializing in the purpose. Most of the working breeds are more readily trained for protection work than the pit breeds. While some may consider the large head and broad jaws of the Stafford intimidating, the Belgian Malanois or German Shepherd with their sleek heads and high bellies are much more likely to attack the boogie man that you fear than a game-bred Bull and Terrier.