I am not in favour of the breed. I can understand that there are good people out there who really love their pit bull dog, and who put in the time and money to train and care for the dogs properly. If people do this then owning a pit bull is fine.
But the wider and more realistic picture is that many people are not doing this. This breed - and several others, can be very dangerous in the wrong hands and with people who don't know what they are doing. This breed has become a status symbol for 'tough guys' and its often associated with crime.
Its in this dogs instincts to fight and be dominant with other dogs. Also once a fight is started they are bred to keep going and go into a 'fight' mode which is very difficult to break. During this time the dog will ignore everything else around it.....even if its in bad pain.
Many breeds of dogs have been bred for hundreds of years for particular behavioural traits. A lab, to retrieve, a sheep dog to herd, a terrier to kill small vermin. These breeds can be trained not to do these things, but its always there in their make up and can surface at any time given the appropriate situation.
Sure smaller dogs can be aggressive and dangerous, but given the choice of an attack by a Yorkshire terrier or a pit bull, I know which one I would choose.
Having such a large, powerful and potentially dangerous animal as a common pet is not a good idea. Its like owning a firearm. In the right hands there is no danger to other people, but in the wrong hands it can be deadly.
If people stopped breeding this type of dog then the breed would naturally die out and there would be no more problem.