Yes, these types of things do happen. But still, to completely close the restaurant seems a little extreme. And the fact the the OP had made a specific reservation for that date, only to find it closed, I think it's a valid complaint. The manager of the store should have offered some sort of discount for the OP to use towards the next dining trip.

I could understand if it was someone random walking in off the street on a whim to grab a bite to eat. But the OP had made plans in advance, was given the reservation (which you usually have to leave your name and phone number to do, at least that's how it worked at restaurants I've worked at), so at the very least, he should have received a call from the store to let him know there was a problem, and he wouldn't be able to eat there.

Although, to assume this location would be closed on Thanksgiving just because the one day he went, they had some sort of employee call-off crisis is sort of going overboard.