Did you actually read the first study you linked? It's not really showing what you're claiming it shows, if you look into it. The test found that 13 percent, or one out of seven, pit bulls tried to bite or attack during a one hour test simulating a neighborhood walk. One out of seven pit bulls tried to bite in the span of just one hour compared to only one out of 70 golden retrievers. They found "no significant difference" between breeds when the definition of aggression was watered down to include even whining or crying. But pay close attention to Table 5 on page 138: out of all the breeds tested, pit bulls were markedly the worst when it came to the percentage of dogs that reached a more serious level of aggression.

The second link doesn't say anything about dog aggression.

In this study Pit Bulls scored high on aggression specifically directed to other dogs. More than 20% of Akitas, Jack Russell Terriers and Pit Bull Terriers were reported as displaying serious aggression toward unfamiliar dogs. Golden Retrievers, Labradors Retrievers, Bernese Mountain Dogs, Brittany Spaniels, Greyhounds and Whippets were the least aggressive toward both humans and dogs.

The interactive dangerous dogs map kept by the city of Minneapolis is maintained in a "breed-neutral" way in that MSP does not "discriminate against" pit bulls. Still, 70% of the dogs listed as dangerous are pit bulls; 81% are pit bulls plus closely-related bully breeds. This map includes reasons why the dogs are listed as dangerous- many are dog-on-dog attacks from Pit Bulls.

In this UK study the most reported attacking breed was the Staffordshire bull terrier in dog-on-dog attacks.

Then here's more somewhat anecdotal evidence coming straight from Pit Bull lovers and advocates!