fair enough trotter.
I'm very defensive over certain dogs that people class as dangerous - its disgusting that things like this happen, but 99% of the time, its the stupidity of the owners that is the root cause and not directly the dog.
For example, all mastiff breeds (Bullmastiff, french/Neapolitan Mastiff, Boxer) are very placid in their nature, they were bred to assist gamekeepers in catching poachers - not to bite or attack them, but to down them and keep them there till the gamekeeper caught up to reprimand them. It is not in the nature of the breed to 'attack', these dogs are very loyal and territorial - thus, they are protective of their environments and close family. The danger comes from them when they detect what they perceive as a threat - such as a child having a paddy or pulling on its neck etc, they do not 'attack' the child through biting - but have a tendency to sit on them and bite the arms and legs to make the 'threat' submit, the owner should not have attacked the dog with a knife but firmly removed the dog from the child and gave it a fucking good kicking... maybe contemplated getting rid of the dog as well, this could have saved the child's life.
I've had a bullmastiff for 4 years now, my son is 36 months old and both son and dog have a great relationship - the way to prevent a territorial and protective dog is to allow them both to interact in the family environment, the dog will then become protective as the child as if its part of his 'pack' and does not see the child as a threat to the 'pack'
issues arise when these dogs are locked away from children and thus perceive them as a threat to the dogs natural 'alpha' status in the home.