"any dog can turn" that statement is, quite frankly, bullshit.
This notion that any dog can turn without provocation is rubbish but is a myth that people seem to insist on spouting to justify their hatred/mistrust of all dogs.
The reality is that it is extremely rare for a dog to bite unprovoked or without being primed to do so. If you look back at dog bites that have appeared in the news over the past few years, one of the overwhelming factors about all of them is that they were already known to be agressive. Rottweillers kept as guard dogs/never allowed inside because unused to children; the staffy and jrt that killed a baby were kept as guard dogs; the little girl killed by a pitbul cross at her grandmother's house the dog was an illegal breed bred for its agression, and another overwhelming factor is that almost all of these attacks have happened away from the child's home but somewhere else where the child was not known to the dog.
People need to get past this hysterical idea that any dog can just turn into a monster capable of savaging and possibly killing your child without so much as a hint that it might happen - because that is simply not true.
As for staffies - unfortunately they have bad press because they are:
A kept as status symbols by idiots who have no idea how to treat them propertly.
B they are known to be agressive towards other dogs, and to most people a dog showing agression to another dog automatically equals agression towards people too when actually there is no corollation between the two.
C they have immensely powerful jaws, more so than say, the labrador, and as such if they do bite the damage they can inflict is that much greater, as such people are put off.
I wouldn't own a staffy based on their reputation for being dog-agressive (and that is a reputation that is upheld by even the experts), but that doesn't mean I think they're all child-killing monsters.
In fact the highest proportion of dog bites in this country are attributed to the golden retriever, yet most people wouldn't think it possible..