It is true that pit bulls make up a hugely disproportionate number of reported dog attacks, it's also true that they are especially dangerous and have caused the most deaths by dog bite.
What many of these statistics fail to account for are environmental factors (pit bulls tend to be the most abused and most regularly abandoned dogs because of dog fighting and also because they are just a handful to properly train and care for.), it is also very difficult to gather accurate data on breed specific attacks/aggression because while pit bulls are the highest reported in most dog bite statistics, they are also not a breed as much as a group of breeds that includes:
The American Pit Bull Terrier
The American Staffordshire Terrier
The Staffordshire Bull Terrier, and
The American Bully
A study found that dogs classified as Pit Bulls only had 43.5% DNA from Pit Bull-type ancestry.
The study, carried out in two shelters in California and Arizona, also found that 62% of dogs labeled as Pit Bulls had less than a 50% DNA concentration from Pit Bull-type ancestry, Pit Bull facts and statistics show.
Identifying the right breed of dog in attacks and death is incredibly difficult. This is why the CDC stopped collecting breed-specific data in dog bite-related fatalities (DBRF) in 1998.
The fact that there’s no official data to go by makes it even harder to separate myths from facts regarding Pit Bull attacks in the US.
Okay cool, so pits might make headlines more because of their strength and ability to inflict fatal wounds easier than other breeds but that goes for most large dogs.
German Shepherds had a similar stigma back when Americans were still xenophobic toward German immigrants and there were similar attitudes around that breed in the mid twentieth century. Prior to WWII Pit Bulls were a working class icon and were as much or more known for their reputation as great working dogs and loyal and loving family dogs as fighting dogs or vicious guard dogs.
Pit Bulls were bred for a wide variety of reasons and selected for many different traits but like most dogs they were foremost bread for physical traits and secondly for their temperament toward humans.
So what happened?
Racism it's always racism.
No new owner may settle in the area so long as they possess such a dog. Critics argue that these bans are not based on sound scientific or statistical evidence—that pit bulls pose no greater risk than any other breed of dog. Advocates of these laws urge that the bans are crucial to protect the public health and safety from dangerous dogs. Yet, perhaps these concerns have less to do with dogs and more to do with the individuals who own them. Breed-specific legislation may be being used as a new form of redlining to keep minorities out of majority-white neighborhoods.
“We don’t want those people here,” a city council member said of the bans. Strong cultural ties exist between pit bull dogs and the Black community. The same is true of the Latino community. Research undertaken here to investigate this claim suggests that people of color are perceived to be the most likely owner of this breed of dog. While at the present time, actual ownership data is not available, if true ownership resembles the perceived distribution measured here, such a finding may form the basis for a legal claim. Under new law, breed-specific legislation could be challenged under the Fair Housing Act if it can be shown that these laws are disproportionately excluding minority groups.
-The Black Man's Dog: The Social Context of Breed Specific Legislation, by Ann Linder
https://law.lclark.edu/live/files/32171-25-1-third-articlepdf
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6107223/
https://www.avma.org/sites/default/files/resources/javma_000915_fatalattacks.pdf