Ime, homeless dogs are usually calm, friendly, and well-behaved. They are socialised 24/7, they have ample stimulation and exercise, and constant companionship and supervision. In the cases where charities ensure medical and nutritional needs are met these dogs have a better life than most pets.
Ditto the young men who drag their unleashed staffies everywhere, they generally have friendly, affable dogs because they drag them everywhere, unleashed from day 1, ensuring the dogs have very good socialisation and stimulation.
Saying that, I don't think my town, or any town I visit regularly, is the norm. I don't have the same experience of numerous out-of-control dogs and being accosted by aggressive dogs every time I leave the house like the majority of MNetters.