I know plenty of people who own PBTs and who have never had a problem with them.
I also know a very snappy Jack Russell, a stroppy arsed Collie and 3 or 4 Labradors who I wouldn't trust with children.
Have you ever heard of the organisation "Deed Not Breed"?
(Reassurance to regulars who are fed up with me stating the bleeding obvious speaking in defence of dogs - I have visitors soon so you won't have to put up with me all evening).
Val - independent network dog/other animal rescuer, dog rescue volunteer, dog fosterer, person who is fed up with stupid generalisations about dog breeds.