Wow. That is really sad. I'm not a big fan of pit bulls but aren't biased against them so much as I am biased against many people who choose pit bulls to be badass. While I generally agree that pit bulls have a greater propensity than most other dogs to be aggressive, I can't help but wonder how much training and socialization this particular dog had, no to mention proper breeding. I acknowledge that there are some great pit bulls out there.
I say this as a Rottweiler owner and that breed has a bad reputation too. We got a well bred dog and went to great lengths to train and make sure our pup is well socialized with people of all ages. That is important for any breed of dog. Not to take this on a tangent but we recently had our Rottweiler at a dog park and a Labradoodle attacked him without any provocation. Ban Labradoodles! I hate dog parks.