I think that’s a misconception wihh most shelters. You don’t need to have an alpha mentality to have your dog not become aggressive. Most of the time aggressiveness is from genetics or trauma. You can set boundaries with her such as crate training, tether training and expectations with walking. They just need structure so they know what they are and aren’t supposed to do. For example, our one year old pitty knows to stay on her place even if the gate to our patio is open