It's simple: He's using it as cover by keeping a perpetual state of high security to hide the comings and goings of foreign diplomats he's making illegal back room deals with.

Traditionally, people notice when there's extra activity around the Whitehouse. By creating heavy security and a "green zone" around the Whitehouse, he doesn't need to increase security when someone like a Chinese diplomat or anyone else he's dealing with arrives through the tunnels to discuss the selling out of America.

After all, the Chinese aren't entirely stupid. They know you don't discuss the selling out of a country within its own borders without security assurances. So Biden keeps the security high 24/7 to obscure the timing of the meetings.

That's what this March 4th militia hoax is about. Biden is probably meeting with someone of particular importance, possibly even Xi himself. So he needs an excuse to up security to their satisfaction. Creating the militia lie just allows them to have a politically beneficial excuse.