Why Micromanage?

What is the cause of a lack of trust a leader has with a team? There are many reasons for someone to withhold trust. One of the most unfortunate is when a leader doesn’t believe in his team. Perhaps it’s an insecurity that I won’t be needed or necessary if a teammate shines without my direct involvement. Another reason could be a stubborn conviction in one preferred method over any others. If a teammate discovers another way, I might feel the threat of being invalidated. The irony is that when I am oppressive in my micromanagement, I communicate all these insecurities to the entire team. We all leak and nothing leaks insecurity like micromanagement.