Tell me you know nothing about pitbulls without telling me.
Initially they were bred to fight dogs, BUT any fighting dog who attacked a human was banned for life and therefore useless to the owner and they got rid of them. If you get a pit bull from a reputable breeder they will love humans. Having said that, obviously it's a powerful breed and you have to raise them right and behave like a pack leader, which seems to me didn't happen with this one.
Also, blanket bans are stupid! There's way more people who die every year due to drunk drivers, but I never hear anyone say let's ban alcohol.
The solution is to introduce a keeper's license for all dog breeds, one has to aquire first before they're allowed to keep a dog. Therefore anyone potential keeper would have to prove first that they're capable of socializing, raising and training a dog the right way before they can get one. This would eliminate most of the attacks.