Thank you for sharing the story of Sergeant Stubby, what a special dog. I have never personally owned a pit bull due to my living situation (condo) but I know a few people that have and they are very loyal. The city I live in has seen its share of pit bull related problems. Tia Torres of Villalobos Rescue Center (she has a show on Animal Planet called Pit Bulls and Parolees) personally came to our city to save a pit bull on death row.
A big reason pit bulls are used for fighting is their strong will to please their human. It breaks my heart when I see fighting rings busted and the dogs are wagging their tails and giving kisses, only to be euthanized due to their dog aggression from being fighters. Pits that have fought can be rehabilitated. Best Friends Animal Society did it with the Michael Vick dogs, now that was a group of some very damaged souls. Now many of them are living happy lives as family pets.
No living creature should ever be put to death because of what breed they are.