I don't think the person actually got a separate menu.
I think they got confused.
There is a general tso's-type item that is a hot appetizer. I think some combination of them not reading the menu carefully, the waiter not being clear, and vacation memory fog contributed to the misunderstanding.
I'm guessing one of two things happened:
1.) They saw it on the menu, tried to order it and were told they couldn't. Maybe the waiter said it was only included on the deluxe dining plan without clarifying why or that it was an appetizer, and the person misunderstood the situation.
2.) They didn't see it as an entree, asked for it, and the waiter misunderstood and told them it was only available if they had the deluxe DDP, again, without explaining clearly that it was an appetizer.