I'm going to jump in here once again.
I would never advocate banning a breed of dog. I would advocate banning the breeders. Ok, that's just sarcasm, but it could be one answer.
I would also not advocate killing an animal because it looks dangerous. I would, however, kill an animal if I thought my life or someone elses life was in danger. However, an animal that has been proven to be vicious should be put down. Then the owner should be put down, because the reason the animal is vicious is the owner. Ok, that was some more sarcasm.
I believe that an animal can be vicious because of it's personality, animals also have distinct personalities. Hell, people can be bad because of their personality. What do you do with either of them? One gets put down, the other goes to jail or gets put down. That isn't sarcasm, it's fact.
Animals can also be vicious because they are trained to be vicious. Many people own big, scary dogs, so they can feel tough and scary themselves. Those people may very well train their dogs to be mean. Those people should be banned from owning dogs or any animal.
An American Pit Bull in my old neighborhood was put down because his owner kept letting him out in the neighborhood. The dog killed several other dogs and cats in the neighborhood because he was trained to do so. The dog killed my wife's cat and the cat was in our screen porch at the time. The dog was finally captured and there was a trial in the county court. The Judge was furious with the owners and very upset because she had no recourse but to have the animal destroyed. She owned Pit Bulls herself and loved animals. There was a very heavy fine and all of the owner's other animals were confiscated.
There is not a real solution that you will come up with in this thread. I certainly don't have an answer. Maybe people should have to obtain a license to own a pet.