I agree with you. My mother in law is like that about pit bulls. She says she saw a man on tv get bit my one on the face so now she thinks all pit bulls do the same.
I don't trust the owners of that and other certain breeds that can be vicious to train their dogs appropriately. for that reason I avoid certain dogs more than others, that being said I do not try to pet or get close to any dog I don't know, but I use more cation with some more than others.... I may be wrong but that's my choice, and I would like to be proven wrong more than to be proven correct.