Lack of Food during Holidays

I just don't get it. Why do all the canteens in NUS want to close on a public holiday. There are still so many people on campus looking for food. Even Fong Seng had only one stall open, resulting in a very long queue. In the end, I had to settle for Mcdonalds even though the queue there was long as well. If any NUS canteen opens on a public holiday, it will surely monopolize!