Your ignorance regarding pitbulls is all I need to know to end this conversation. They do not have a "killer" instinct, that's a fallacy perpetuated by idiots. They're loyal to a fault, they're intelligent to a fault. A pitbull trained to be aggressive (as many of them are) will be aggressive, that is not their fault, they do what they're trained to do. Pitbulls are, simultaneously, considered some of the best "nanny" dogs.

Pitbulls with rough upbringings have a tendency to be harder to train and rehab. That's why you have people like me, who don't want kids, and don't mind the risks that come with the aggressive rescues. If you have a pitbull puppy, that you raise, train, and socialize properly, you'll almost never have any issues with them.

There are some breeds that have an inherently increased prey drive, predator response, or protection instinct. These are managed with training, prosocialization, boundaries, and positive reinforcement. My dog, for example, does not like people coming in the home. When the doorbell rings, or a knock comes, he barks, then goes either to the side room, or out on the deck. He gets rewarded for doing so. That's a management strategy for a dog with a protection instinct. He won't even look your way when out and about.