No, they are not incompetent one bit - they move well over a million people several times a day through the Metro.
It depends whose in power to be honest - when the Million Man March went on they ran rush-hour service for the miserable crowd that showed up.
Part of it is political, the other part, and lets be honest about this, our side has only just started to really ramp up pro-America demonstrations at in DC in huge numbers. The left believes they own the sole right to protest and have held that belief since the demonstrations over Vietnam.
I honestly believe Metro Admin thought that many people would show up for a right-wing event. When it happened, well they had to do something about it, after all, who do these right-wingers think they are coming to DC to protest!!!
Perhaps incompetent is too harsh a word, maybe they were just inept.