I wrote these two posts in another forum, but they are applicable here.
That sounds like "I don't like black people because everyone knows they steal and they could snap at any second."
Doggie discrimination!
No dog is bred to be evil. Dogs are trained to be evil. Dogs also react different to stimuli than we would. People who are around dogs need to learn to to show behavior that fits in the dog's mentality, that is how we can communicate and live with them effectively.
I am sorry, but if a dog, even if previously exposed to a person starts behaving differently, there is a change in the environment that would explain that change. Not to mention there would have to be something YOU do to provoke an attack.
When my mom was pregnant with my little sister, our dog at that time, a mix Springer Spaniel - Blue Heeler was very protective. The dog would go into a threaten posture when men he knew approched the house with my mom inside. My dad made a quick movement towards my mom (for affection, but the dog saw only the quick movement) and the dog immediately went to protect my mom, but backed down as my dad moved away from her. Normal speed movements did not trigger the dogs protective instinct at all. After my little sister was born, the dog went back to normal behavior, back to his friendly self and never threatened anyone.
As much as people try to anthropomorphize dogs, that will never work. To be a good dog owner, you need to understand how the dog reacts to ourtside stimulus and act accordingly. I get away with things with my dog that no other person would be as I established pack order early. I also make sure guests in my home don't do things that would trigger the dogs less social responses. Anyone that says ANY dog "would never bite" is an idiot. ALL dogs can bite. Good socialization, good training and KNOWING how dogs react to things if vital for owning ANY pet, especially a 40-70 pound pitbull.
There are different kinds of canine agression. There is human aggressiveness and prey agressiveness. Most dog bite situations are more a result of territorial encroachment or unwanted dominating behavior by the human. As for pit bulls they were trained to first fight bulls, then other pits then they went our of favor as dog fighting gave way to ratting. A human agressive pit bull was unwanted by a trainer as he needed to handle the dog in the ring, often injured. Frequently that involved gettign close to the dog's mouth as pits would tend to bite through their own lips during a fight. The handler would need to grab the dog during a break and push the lip off of the tooth. Most dogs do not like to be handled by the face. it takes trainign from the time the are pups to do this safely and to be trusted by the dog. This need for a lack of human aggression in the "heat of the fight" led to any dog showing human aggressive tendencies to be destroyed or at least no longer bred. But now take German Shepards. They are far more likely to be trained in a "human agressive" role such as a a K-9 police dog, but it has been 40 years since they were considered "evil" by the media and society in general.
So to address your point, if a pit bull does act aggressive towards a human, somethign has been done to the dog to increase it's aggression towards humans or a disreputable breeder has not been careful enough in his selection.
FYI, there are only three actual "breeds" that are true "pit bulls". American Pit Bull Terriers, American Staffordshire Terriers and Stafforshire Bull Terriers. The difference is the group that sets the standard for the breed. The most restrictive is the British Kennel Club's Staffordshire Terrier definition. The American Kennel Club and the United Kennel Club have slightly different definitions based on certain characteristics. However, there are up to 25 pure breeds that can easily get mistaken for a "pit bull".
In fact here a couple of websites that challenge your ability to find the "pit bull"
http://members.aol.com/radogz/find.htmlhttp://www.pitbullsontheweb.com/petbull/findpit.htmlBreeders and puppy mills have a lot to answer for with the current situation. There is not nearly enough regulation for breeding dogs.
Hell, there isnt enough regulation for breeding humans.