It's a matter of risk. Sure, there's some distant possible world where she hurts somebody. But there's also a distant possible world where my 17 year old son attacks someone in the park. Does this miniscule risk mean I should keep my teenager on a leash in public? Of course not. You guys are just not thinking clearly about the role of risk in public life. There is functionally no risk of my dog, or my teenager, attacking someone in the park. That's sufficient to have them off leash.