Tongue in cheek but everywhere I’ve worked has had some sort of work order system whether it was for facility maintenance, IT, or supply ordering. Random people being able to grab support staff and task them is inefficient and makes it impossible to prioritize work.
The president is not a member of the military, neither technically nor otherwise. The military is under civilian command.
Same with the Secretary of Defense, the branch secretaries, the assistant secretaries, and anyone else in the DOD Senior Executive Service. They are all part of the civilian control of the military but they are not in the military. If any committed crimes it would be heard in federal court not a court martial.