I don`t think the breed makes a lot of difference, it`s how the dogs are reared and trained that`s the deciding factor. We had a German Shepherd years ago, and never an ounce of bother with him, and our daughter and her husband have had 3, the current one is an absolute darling, it just depends how well they are trained. I`ve known several Staffies, only one showed any sign of being nasty, and that was to other dogs, never people.
If the dog in the news was wering a muzzle to start with, it was completely irresponsible and criminal of the owner to remove it and let the dog run free.