Be mindful when reading the sources. This is a very polarizing debate, and it isn't really as clear as "pitbulls are little angelbaby velvethippos" or "pitbulls are vicious killing machines".

Pitbull is a range of phenotypes, not a breed. What we call pitbulls commonly are a mix of boxers, Am Staffs, bulldogs, american pit bull terriers, bull terriers, etc. So, we're relying on police to ID these dogs after a bite has been reported, and so a large number of aggressive individuals of a variety of breeds/mutts might get lumped into "pitbull" by cops.

Also, dog attacks are more likely to occur in lower socioeconomic status neighborhoods where dog ownership practices are often less responsible, and cops are more likely to be in the first place. Pitbull-type dogs are more likely to be owned by lower SES individuals (in part because they're so prevalent, but also due to cultural factors). So, it is likely that pitbull-type dogs are overrepresented by these statistics.

That said, it is wild that people claim that breeding does not impact behavior. Pitbulls and various bully breeds have often been bred to be aggressive and to guard territory, just like Cattle Dogs have been bred to nip at heels and keep creatures in a herd. Any cattle dog owner will tell you that their dog exhibits herding behavior even if it's never seen a cow or sheep. It's the same with some pitbulls and they happen to have one of the strongest bites of any type of dog coupled with a behavior where they latch on to the thing they've bitten and won't let go, but will continue to thrash around causing major tissue damage. Contrast that to German Shepherds, another dog that makes up a large number of dog bite cases. Their bite force is less on average than that of a pitbull and most German Shepherd bites are fear-aggression related because GSDs are extremely neurotic and anxious (also due to breeding), so GSDs tend to bite and release unless they're specifically bite trained, like for police work.

So anyway, just be aware that both sides of this debate try to put spin on it, but breed characteristics do matter, and our recordkeeping of dog breeds and bite statistics is flawed essentially due to the problems extant in law enforcement broadly.

https://www.forbes.com/advisor/legal/dog-attack-statistics-breed/

Dog Attack Statistics by Breed

Many dog advocates argue that there is no such thing as a bad breed, only a bad owner. Still, it can be helpful to understand which breeds of dogs are most commonly involved in bite incidents or acts of aggression. Dog attacks by breed statistics are invaluable both for individuals looking for a dog to adopt as well as for those who interact with animals who want to minimize risk.

The breed that commits the most attacks overall is pit bulls.

Pit bulls are involved in more dog attacks than any other breed. In fact, the American Animal Hospital Association reports this breed was responsible for 22.5% of bites across all studies. Mixed breeds were a close second at 21.2% and German Shepherds were the third most dangerous breed, involved in 17.8% of bite incidents.⁶

The breed that is most likely to be involved in a fatal attack is pit bulls.

Pit bulls are both more likely to be involved in bite incidents and more likely to cause serious injury or death when a bite does occur. In fact, from 1979 to 1998, the Centers for Disease Control and Prevention determined pit bulls were involved in the most fatal dog attacks, accounting for 28% deaths due to dog bites during that same time period.⁷

I'll add, I like pitties. I'll also advise taking this with a grain of salt as so many mixed breed dogs fall into the pitbull umbrella.

The stats are easily manipulated by either side. The fact of the matter is that, given the number of attacks on humans and animals by pit bulls, and the average age of pits, roughly 1 in 10,000 pits will attack something in their life. This is an order of magnitude more frequent than rottweilers (the next most dangerous breed), and when a pit bull attacks, it's more likely to kill its victim than any other dog breed.

1 in 10,000 is large enough for some people to say the whole breed needs to be euthanized, it's small enough for some people to say that it's negligible, and it's at just the right spot for me to say that it should be illegal to breed them, but existing ones shouldn't be euthanized.

There seem to be two sides to this debate, where one side insists that these breeds are inherently aggressive and the other side insists it isn't true.

Too many people believe whatever they want to believe.

Certainly some dogs of specific breeds are less aggressive than others but all dogs have been bred to have some sort of specific trait(s) (small, large, fluffy, "cute", fast, intelligent, etc) and some breeds were explicitly bred to be aggressive.

People want to believe certain breeds aren't inherently aggressive because it leads to exactly this type of problem.

I don't know that it's possible to quantify aggressiveness.

The solution is to heavily regulate breeding and associated sales because that's exactly what creates the surplus of animals no one wants to take care of, and its something people should consider before buying any animals at all.

All you've gotta do is Google 'human fatalities by dog breed chart" the numbers are all that matters, and frankly I'm annoyed that the data isn't enough to deter people from owning these dogs. A friend from grade school had 1 attack his daughter to the point where the kid was hospitalized. They had that dog euthanized, and went right out and got another pit bull. You can't fix stupid.