I agree that even middling quality middle managers provide plenty of value, but there definitely is a class of manager that does not know how to engage with all of their employee charges and make them effective. Most of the egregious side hustle situations I've run into have come from particular employees that felt they were so close to the chopping block that it didn't matter anyway, as they felt abandoned by their management chain either perceived or in fact. Most others have at least been respectful that the full time salary = time priority and because of that and reasonable task management it became not a problem.