I don't think anyone believes that a "barked command" to smile is anything but rude. But someone saying "smile" or words to that effect =/= a barked command necessarily. Again, if there is aggression at any point, that's rude and inappropriate. But simply saying smile, while possibly annoying, is not rude.
I don't think it's entitled or patriarchal behaviour either: it can just be a bit annoying. No biggie.