Unfortunately the grabbing and shaking was bred into the various pit types/breeds for better dog fighting.
The bulldog origin (not modern old English bulldogs) was bred specifically for 2 traits: Going for the face/head and grabbing and holding on without letting go regardless of what was happening. The original bulldogs were used for either livestock handling (around fractious bulls) or large animal sport baiting. (bulls, bears, etc) The jaws are shaped specifically for that, the under-bite for better grip and being able to breath while not letting go or having to adjust their grip.
When large animal baiting was outlawed they started fighting the dogs against one another. They added in smaller dogs for better agility, choosing various types of terriers due to the matching “never back down, never let go” and adding in the desirable shaking. Terriers grab and shake. It’s how they kill, what they were designed for. Killing pests. The fast snapping shake from a fast agile dog without a meek bone in it’s body was what kept the small dogs from being injured by rats or whatever they were bred to go after. Shaking when holding on to another dog increased damage, the terrier personality added more chutzpah to the bully personality.
Overly human aggressive dogs were culled mercilessly.
Nowadays and for many generations nobody culls them like they used to be.
So in short the AmStaff, APBT, et al are all predisposed to be dog aggressive, aim for the head, bite and shake. Will they all do that? No, just like all bassets won’t chase rabbits. And all huskies won’t try to yank you off your feet when leashed.
BUT, when any of these dogs do something completely and totally out of the blue without any input from it’s human or any indication from the way it was raised and handled but something it was specifically created for…we shouldn’t be shocked or surprised or pretend our love/regard for it nullifies it’s genetic-bred traits.
As stated before…it does not make any of these dogs bad, it makes them exactly what they were created for. And they can be bred, raised, handled and owned by people with little to no incidents.
HOWEVER…some breeds/types really really really benefit from only being bred, raised, handled and owned by a very small percentage of experienced, realistic people. There simply isn’t any public relations angles or propaganda that’s going to change that.