I believe there should be some limits. The neutering thing sounds good.
When I volunteered in a veterinary clinic, only pit bull owners were required to wait with their dogs in their cars instead of the waiting room.
In the three years I've lived here, my friend had to go to the emergency room because of a pit bull attack, and the same dog later put her neighbor in the hospital. In addition, the first time my dog went to a dog park (6 months old), she was attacked by a pit bull. We took her back about three times, to various parks), hoping that she would learn how to interact. She was never attacked again, but we saw about 6 attacks there by pit bulls (always on smaller dogs of other breeds). Fortunately, only one was very injured. We no longer take her to dog parks, as she is now frightened by any dog.
I don't blame the dogs, but some of their owners are sure dropping the ball, to put it mildly. When the park attacks occurred, the dogs would be leashed by the owners for a minute or so, then released (against park rules) to start another fight. I have wondered at the solution. I wish the parks were officially monitored. Also, it seems it would be a good idea to fence off part of the park where only pit bulls would go. Then, their owners would be less likely to allow them to fight - or would they?