This is just city hall, the representatives of the voters. This is arrogant and privilege taken too far. One doesn't snap to attention when a representative or senator enters a room. Why so with just a mayor?
I wasn’t there to assess the situation, and neither were you. If it was out of order, I know how I would react. Honor where honor is due, and vice versa. As a subordinate on any job, deference to a superior is in order. Otherwise you might have a little something extra in your paycheck: a pink slip. But at least you would have your integrity, wouldn’t you?