Why do district managers ignore shitty leadership?

I’ve noticed that while district usually makes their managers at a store fix a lot of issues of their products, fixtures, customer satisfaction. How come they always ignore problematic leadership. For example, people in higher up positions that harass their associates. I’ve worked at a store where basically every leader was a nasty bully to others and aren’t actually good at their jobs. They’ve caused several people to quit and have gotten caught sexually harassing several people. Who’ve also committed several crimes which was well known around the county. Yet, they’ve kept their jobs. I really feel like they actually wanted to increase store success they wouldn’t keep managers like that.