Samuel - Thank you for helping us to make the distinction. I believe it's a boundary and control issue.
I like to think of micromanaging as a symptom. It alerts us to the fact that someone may be struggling with one or more passage in the leadership pipeline. It can be damaging to an organization if left unchecked, but I don't think it's uncommon or uncorrectable. If I were coaching a micro-manager, we would be talking about boundaries and how they move as we climb up the ladder. I'd leave things like control, trust and insecurity out of the discussion if possible. They are implied in the situation and can be a downer if given too much attention.