Trump is still the President and commander in chief. He technically commands these troops. Biden can't call up all of these troops as the president elect.
You need to rethink your theory.
It is a very common human error to look at an organization chart and think that is how the organization works.
It is also very wrong most of the time.
In the case of DC the Deep State is the default ruler. They are _not_ elected and continue from administration to administration.
They ordered the National Guard out there...
You are correct. Any idea why President Trump ordered military troops to DC?