The text in in the tweet poorly captures what is reported in the video.
Since DC does NOT HAVE A GOVERNOR, the Sec of the Army is the one who can activate the National Guard for DC, and this seems to be what has happened. Although the reporter SAID that the Sec "becomes the governor" that is just poor speech.
Article I, Section 8 of the Constitution gives control of DC to Congress, which devolved most of its powers to DC via the Home Rule Act. There is NO SUCH THING as the governor of DC.
And there is no sign that POTUS is yet doing anything under the Insurrection Act that Q mentioned, which would be a different story.