Original Message

Maybe it was someone else who did something and the guy doesn't want to single him out and sends an all hands message? One possible explanation, but I have no context.

Another might be that his boss said tell crews....

'maybe there's a common mistake folks are making, and you're not one of them...but others need the reminder.

micromnaging, for a pilot, would be something like being in the cockpit telling you which decisions to make. An email is just annoyance management.