I think there's a bit of honesty to it as well. I bet the burglars need to see themselves as breaking into Mordor and challenging Sauron to save Middle-Earth. As much as Congress houses difficult things like partisan deadlock and lobbying, it's not a villain's lair in an action movie. I think it was smart of the capitol organizers to ensure Congress was secure, and then stay away from posturing like a James Bond villain.