Can I order 5 minutes before closing time?

But my friend said I was rude.

We were taking a walk last weekend and went past the eatery on the way back. I was hungry so I just wanted to buy something to eat.

The diner had a sign saying it closes at 10 p.m., which means they are going to serve a customer coming at 9:59 p.m. If a place wants to close exactly at 10 p.m., it can just stop receiving customers half an hour earlier. Banks do that. They technically close at 5 p.m. but stop receiving customers from 4:30 or even 4 p.m.

My friend said that I was very impolite when ordering 5 minutes before closing time, that I cannot compare banks with diners, because people working at the latter still have to clean up the place. Also, if they already turn off ovens and put the ingredients away, they are going to have to turn them all on and lay things out all over again.

My friend said that if everyone thinks like me, diner staff will have to work very late, and they are not going to get paid more.

Can you please tell me if I was wrong?