In all of these cases the owners say "He/She was so gentle, I would have never expected he/she to do this"
I can understand that no one expects their pet to do something like that, but we must all remember that they are pack animals, and to them a stranger is a threat to the pack.
My views are slightly skewed when it comes to pit bull type dogs, as I don't like them at all. And from what I understand they were initially breed for fighting, and when it comes to selective breeding only the traits that are wanted are breed into the dog.
What are your views on this?
Oh also, I do commend the recent cases the owners have said "I don't trust the dog anymore so put it down" It must be hard for them, but i respect them for taking the correct action IMO.