Time and place is correct. Few of us can go to a job and say/do just anything we please. If you are paid by an employer you are there for their purposes and they can set conditions. Pro athletes can do all the free speech and demonstrations they like on their own time, their own dime. But when they are in uniform for a TEAM the organization has every right to set professional expectations.
When I was working as a flight attendant, I remember there was another flight attendant who went to a Letterman show taping during her layover in New York. She was not in uniform, but Letterman was doing his audience shtick and got her to tell him who she worked for and how she really felt about passengers. "The passenger is the enemy," she said, and got a huge laugh.
Letterman took that and ran with it. Kept mentioning it throughout the show. "Come fly with us, where we treat you like the enemy!"
She got fired before she even got back to the hotel. Had to buy her own plane ticket home.
You do not embarrass your employer, and you definitely do not belittle, degrade or humiliate your customers.