If the place is open it shouldnt matter where it is located, they are there to do business and sell food. Really as a business owner or manager of a retail location, you are going to turn away a huge order, that you have the food for, when you have explained to the customer that it may take a few minutes longer bc your staff is smaller.

That seems foolish wherever you are located.
When I worked in a pharmacy, if a customer walked in at 2minutes to closing, the pharmacist would stay until the customer had their medicine. I stayed many a nights after closing as someone waited for the meds bc we never wanted any employee in the store with money and drugs. Now if they wanted to shop for a long time, they would be reminded that we are closing and ask them to please make their purchase quickly. But we never turned anyone away until it was past closing time.
Maybe location does have something to do with it bc I live near a college town and none of these places would turn away a huge order, even if it was late at night.
It is not good business to turn folks away who have money that they want to spend on your product, esp a PERISHABLE product like food.
I dont know about demanding, but if the manager/owner was good at their job they would have provided you with a reduced rate on an alternate meal (like our KFCs are usually coupled with Taco Bell, maybe sell you some tacos, cheaper) or they should offer you a coupon to come back next time.
Once again Business 101...make the customer want to come back!