"It's all about the owners and their macho-ness and not about the breed or individual dog's nature."
True enough, but they're also capable of extreme violence, and they're strong enough to pull a 2 ton+ sled. That's a lethal combination. Other breeds may account for more bites than the pit, but few are capable of the damage a pit can inflict.
And... While I'm not going to categorize pit owners as largely gang bangers or trailer trash, you do have to admit that breed is really popular with unsavory characters.