“How is it legally different for the government to regulate a requirement to cover ones legs, stomach or other body parts than to regulate covering ones mouth and nose?”
Probably not an appropriate question for the CR but take my word that there are peer-reviewed studies showing why uncovering certain parts of the anatomy may offend pubic sensibility and decency and trigger midflight disruption more than others. Until 2 years ago, there were a few episodes ever year where flights were diverted or passengers removed from planes for “displaying” too much of their real estate. None of those, to my knowledge were either a nose or mouth. Passengers COULD be denied boarding if they openly appeared to have a contagious illness but that rarely happened. All of those rules were specified in the airlines’ filed tariffs. Conversely, the FAA’s authority to promulgate rules (using proper APA procedures were codified in its organic statute and were not changed by airline deregulation which eliminated the CAB).