I would definitely report it. the dog (regardless of breed) was out of control when it attacked the puppy, and there should be some kind of comeback against its owners (even if it just to make them pay the vets bills and/ or compensate)
Agree with DBF, though. SBT's seem to get really misrepresented this way. They are often dog aggressive, but this bears no correlation to the way they interact with humans. I don't know where people get this from. The biggest problem would be if a child got in between 2 aggressive dogs, but even then, especially as, in this case, the dog was called off by a 10yo boy, and without force, apparently, this would be really unlikely
Dogs DO know the difference between people, animals and other dogs. The story is bad enough in itself to warrant reporting. As a vet, I get really wound up at treating doggy victims of other people's uncontrolled dogs
, and really don't believe the police do enough about it, considering the stress and pain it causes dog and owner. You may need to push the police to prosecute, though. I don't think you need to embellish the story by making the dog's breed out to be something it isn't, or to extrapolate that the dog might harm a child the same way. in fact, it might just make you look a bit hysterical, and make it less likely that the police will take you seriously. Good luck, and hope pup is fully recovered soon.