I absolutely loved my brothers staffie. It was loyal loving and a family protector all rolled into one. The key to all this was its training. It basically grew up from a puppy along with my brothers 2 kids aged 4 and 10 at the time it was bought. The vet actually recommended that breed of dog for his family situation at that time. Never had any problems with it. Sadly it passed away a couple of years ago, but never was there a more lovable dog in the family.
that said - It WAS all down to the training. They took it to obedience classes as soon as it was old enough.
Now onto my point - I think people should have to go the dog obedience route when they are getting one of these. They are not for the "stupid". Give a staffie to a fool is a bit like giving a gun to the same person, lethal combination.
With all that said, condolences to the family ect. But i do feel strongly that the keepers should be investigated and if found to be negligent even prosecuted. It may sound harsh ect, but who is responsible ? The baby ? The Dog ? Or the "guardian". Only a fool would leave a baby alone with not one but 2 dogs. May god have mercy on their soul.