I forgot to mention the 2 dogs that I had that were biters were 2 out of 30 to 40 that I have had in my life (I am pretty old). We are supposed to be the pack leader and we must control our dogs. I guess your dog roams the neighborhood doing what dogs do, turning over garbage cans and pooping on other peoples yards.
I have had several dog that I would consider perfect but that came naturally to them. I have one now and he is so sweet and gentle (naturally) that I had him certified as a Therapy Dog.
Hairy and I go to convalescent homes and hospitals where people are stuck for months at a time.
Dog lovers are so glad to see us coming down the hallway, smiles light up their faces.
I didn't train Hairy to be what he is, God just made him that way but I still have to control him on a leash and keep him fenced in the yard so a car doesn't run over him.
I'm on the road quite a bit and it is so upsetting to see a dog wandering by itself along the road or crossing it.
I can't imagine being so thoughtless with my dog.
If I can I track down the owner and let them know their dog is in danger.
Maintaining control of your dog is one of the pillars of responsible dog ownership.
It doesn't mean your dog can never be off leash
but it must be in a context that is safe for him and for other people.