Most of us were likely mentored by managers who grew up with a cop mentality. That's what they taught us because that was all they knew. This model of supervision is a lot closer to law enforcement than it is to enlightened leadership. Cops go out looking for problems to solve. Cops see most people as crooks who will rob them blind if they don't watch them every minute.
Cops believe that they can push employees to perform and that they can motivate with fear.
Following the cop model, many people try to force their staff to perform and expect this approach to work. I don't know if the cop model ever really worked although I will grant you that there was a time when we could more easily get away with it. In fact, being a cop is seldom effective in the long run because it is an external and not an internal force and does not properly address the human factor. In the age of service, a more appropriate management style is coaching. Coaches look for strengths.