I have two dogs. When I'm not around, one is always crated. A couple times a month, I visit my parents who initially reacted uncomfortably to the idea of crating my younger dog when no human was around to supervise her with my older dog.
At first, I thought of spouting the rhetoric that many pit bull owners and rescues share - never trust a pit bull not to fight, pit bulls are bred to fight, pit bulls may not start it but they'll finish it. All these words seemed only to reinforce the notion that pit bulls are really another species masquerading as domestic dogs. I convinced myself these experts were right, but I was ill at ease with their logic.
My answer now has nothing to do with the silly notion that breed determines all but rather on knowing my dogs, of knowing all variables in the equation. My older dog, a pit bull, is kept separate when unsupervised not because of her breed or because of some ancient, innate tendency to eat her companions but because of who she is.
So who is she? Mina is easily aroused by certain stimuli - unknown noises outside the apartment, the mailperson, other dogs, cats, jackrabbits, knocking/ringing door/bell. She is not aroused by children screaming, pigeons, squirrels, pigs, cattle, horses, people she knows outside making noises, car alarms or the sound of fire trucks/sirens. (Those are short lists, of course). I know all this because I watch her, because after 8 years of living with her, I'm pretty familiar with her behaviors.
Mina can go from sleeping-seriously aroused-sleeping quickly and efficiently with the right cues from me. Left to her own devices, she can also work herself up into a frenzy of barking, hackles, shivering and tense alertness. Her method of dealing with overstimulation usually involves grabbing a stuffed animal and toting it around the apartment. If a human touches her during her excitement, she calms down immediately.
But she does not feel the same way about another dog touching her during excitement. If my other dog body slams her while over-stimulated, she snarls or barks her annoyance. I believe firmly that if both of my dogs became overstimulated, they would redirect onto each other, in absense of anything else to distract them. It has never come to this, of course - my younger dog is a bit more laidback (she's more intense in other ways) and my older dog often relies on the cues of my younger dog on how to proceed. More than that, I'm always there to calm both of them down if things escalate (I try to avoid having them escalate).
So now my explanation is not that one of my dogs is a pit bull (my younger very non pit bull dog would redirect onto my older dog under the right circumstances) but that one of my dogs acts stupid when over stimulated. She gets herself into trouble. I acknowledge fully that part of her arousal threshold has to do with her terrier nature - it would be silly of me not to honor all those other pit bull terriers who came before her. But that is not all of it, that is not the WHY of it, it is just part of the equation. The why is knowing my dogs, knowing what sets them off, what calms them down, what makes them happy, angry, afraid. That is more important than the red herring of "well, she's a pit bull, so there".
As I was finishing this post, I read about the sad death of a 21-yr-old man in England who attempted to break up a fight between two German Shepherds who had been left alone in their yard. The two dogs were so aroused and so over stimulated that they redirected onto him, eventually leading to his death. The man was not the owner of the dogs, but the owner's roommate. At some point, the owner was able to calm the dogs enough to stop the attack...but by that point, it was too late. I'm not saying that, had these dogs been supervised or kept separate, that this attack would have never, ever, in a million years happened...shit happens, really bad awful crap that even the most responsible of folks are unable to prevent. Yet the likelihood would have been a lot lower had a) the dogs been supervised and b) they had been supervised by their owner (if it was clear they did not have a strong relationship with the roommate).