Backup communication systems like this are often implemented with the most basic of components to increase reliability and ease of use in stressful situations.

The trade off is sometimes human error happens. It isn't really a big deal since the messages themselves are encrypted inside of a secure facility then transmitted to a non-secure area that handles the actual broadcast (since it would be stupid to put a massive transmitter in the room with your super secrets).

So they’re broadcasting super-secret messages from their living rooms?