The CDC had done a study once & gotten similar statistics to what you've quoted, but ultimately they concluded that the data was flawed & unreliable. However, as I learn more about what's going on, the big picture gets more depressing…
Pit bulls are indeed disproportionately mistreated & improperly trained, far more than any other breed of dog. They're the breed of choice for drug dealers and gangsters in the US, and account for the vast majority of dogs seized by police at dogfighting operations. This isn't by coincidence, as pit bulls have always had a variety of traits that make them ideal for dogfighting.
Originally pit bulls weren't bred to be overly aggressive (even in dogfighting, indiscriminate aggression isn't a desirable trait), but modern pit bulls absolutely are, and this trend is only getting worse as breeders continue to select for increased strength & aggression, traits considered desirable by the criminals & lowlifes that now drive the demand for purebred pit bulls. The CDC suspects that there is a gross misattribution of fatal dog attacks to pit bulls, but now this seems unlikely. In fact, pit bulls that have a reputation for being unaggressive, including the ones that I've personally met, are unlikely to be purebred, and are most probably mutts that merely resemble the breed, if not the descendants of an ever-shrinking lineage that has avoided the vile trends that now plague the modern pit bull.
For me, this has all been very disheartening to discover. When I see the face of a pit bull, I'm reminded of the jolly dogs I used to play with as a kid, not the modern monsters responsible for a growing body count. It was very easy for me to disbelieve, and I'm sure many of the folks who are quick to defend the breed feel the same way…
I wasn't implying that they're all drug dealers' dogs… the point I was making is that the breed is heavily favored by criminals & associated groups that desire an aggressive dog. These groups influence pit bull breeders, who in turn select for aggression, but these same breeders also sell to people who don't associate with such groups and might be unaware of these breeders' practices.
When I say aggression, I usually mean aggression specifically towards people, which seems to be peculiarly intense in pit bulls. Aggression towards other dogs is a given for any dogfighting breed.
I didn't say pit bulls have a reputation for being unaggressive… did you even bother to read what I actually said? I said ‘pit bulls’ that have such a reputation are unlikely to actually be purebred pitbulls, since one would expect modern purebreds to be aggressive, and this might include the dogs I've met that I assumed were pit bulls.
I'm not sure what the point is of the last study you linked.