That's not why pit bulls have a "bad rap." They have a bad rap because the breed has earned it with their killings and maulings across the country. A pit bull that suddenly goes into attack mode is a killer, unlike chihuahuas.
And who do you think is RESPONSIBLE for the breeding and training of such behavior? Hint: It ain’t the dog. My family has owned breeds like Boxers and German Shepards, and we raised them to differentiate between a threat and a six year old. Bottom line: You can thank the owners for the maulings and killings.