I had a staffy that was bought as a puppy by the original owner labeled as an amstaff [illegal breed in the uk]. He was the easiest dog to train I have ever have. I had to get him castrated, because he was unpredicable with other dogs. No visable aggression, he would walk up and try and bite thier neck. Getting the problem cut off and consistant training sorted the problem.
The thing is there too many dogs are owned by people too thick to train them or deal with problem behaviour. I got attacked two weeks ago by two long haired jack russells. The owner was an insiped middle age lady, walking two dogs off a lead on a cycle path. Dogs didnt bite but I could feel its teeth on my leg as I franticly cycled past, all the owner was doing was saying "ooh stop being naughty". If I had a dog that behaved like that I had it would of had it muzzled, and if didnt respond to training euthanised. The same day we walked past a collie off the lead that became aggressive, it was been walked on open grazing common land by again an insiped middle aged woman.
I dont understand why anyone thinks any form of aggression in a dog tollerable, like the numerous dogs that are left in yards that bark at passersby. Breed specific legislation doesnt work, expensive dog licences that come with owner training might be a better idea.