When people RSVP for something, it is considered to be polite to actually show up for the event and not flake out and not bother to come which is exactly what happened in this case
Consider the statement "I organized an event to play flag football, but two guys didn't show up even though they rsvp'ed.". Based on this "Thrilled with how two very responsible guys who RSVP'd for the flag football game didn't bother to show up, so I was stuck with a half-baked event." a true statement? Yes, no, or I don't know?