One of the stereotypes about dog bites is that "all of them happen because of pit bulls." This is, of course, an exaggeration -- but there is a kernel of truth to it. Pit bulls can be aggressive dogs, and they have very powerful bites. As such, when they are involved in a dog bite incident. the likelihood of serious injury is high.
The statistics bear this out too. From 2005 to 2016, there were 392 fatalities related to dog bites. Of these deaths, about 65 percent of them involved a pit bull. If you look at 2016 specifically, there were 31 deaths related to dog bites and 71 percent of them were caused by pit bulls. Even though this breed only accounts for 6 percent of the U.S. dog population, they disproportionately cause fatal harm when they attack people.
While part of the reason is their natural power and jaw strength, another part of the problem is that some dogs simply aren't trained properly. This can happen with all breeds. The problem is that when pit bulls are improperly trained, they become incredibly dangerous animals to not just their owners, but innocent people who are nearby too.
Dog owners have a responsibility not just to themselves and their dogs, but to their community, to ensure that their pet is properly socialized and safe. When they fail to do this, they assume liability when their dog attacks.
Source: DogBites.org, "Dog Bite Statistics -- 2016 U.S. Dog Bite Fatalities," Accessed Feb. 22, 2018