Try getting a home insurance quote through 10 different home insurance companies and see how many will insure Pit Bulls compared to other breeds. These insurance companies look at internal data from their own claims experience and external data from studies. Insurance companies have a financial interest in minimizing risk but also growing their customer base. If there really wasn't a significant difference in risk compared to other breeds they would not be turning potential customers away.

I have family that has a pit bull and it is a very nice dog. I think they are great owners. But looking at the big picture I think it would be better to have some type of licensing or vetting process to be able to own one.