I didn't say that all dogs have the same personality; the different breeds all have their own quirks, and even individuals within a breed cover a wide range of personality types.
But...all dogs are trainable. Some breeds, and some individuals, are easier to train, some are more difficult, but all can be taught to behave in a safe manner. Sadly, one of my father's favourite expressions ("in order to train a dog, you have to be just a little bit smarter than the dog"

) often manifests itself in people who are too lazy to bother training a dog, or not smart enough, or both...but they still have 'em.
When some wannabe tough-guy a-hole gets himself a Pit Bull or Doberman or Rottweiler...because they're
bad-ass dogs, don't ya know...and then does nothing to train it, or worse yet trains it to be an antisocial hairtriggered moron much like himself, trouble is inevitable. That's not the dog's fault; that potential exists in all dogs, and in all people...and must be tempered and controlled by training.
We will likely see more and more breed-specific legislation, which IMHO will simply force these people to move to other breeds, which they will treat the same way and which will be ruined in the same fashion. Keep in mind that when dog-fighting was in its barbarous heyday, one of the prerequisites for a PitBull was that the dog allowed a human to stop a fight by wading in and manually separating the animals, without biting the person. The breed's aggressive tendencies were intended to be directed towards other dogs, and specifically
not people.
Let's face it: we live in a day and age when everybody wants everything to be 100% safe and worry-free, with the gummint protecting us from ourselves at every turn. If dogs had never been domesticated by our ancestors, and some enterprising individual were to suggest today that we take a highly-intelligent pack-hunting aggressive carnivore...and raise it in our homes with our families as a pet or companion...they'd throw him in jail.
I dunno; today, if you want to drive a motor vehicle, or fly a plane, or practice medicine, or charge for almost any professional services you are required to have training and certification. But anybody...
anybody...can have a dog (or a kid), and many pet owners and parents prove to be shockingly incapable of performing those roles in an intelligent and safe manner.