I *seriously* beg to differ
Attitudes like yours are why hundreds of people sometimes die in airliner crashes. Suppose it were the FO who questioned. If company policy (like that of Korean Air) told him or her to simply sit there and shut up and take orders from the captain, would it have been wrong of him or her to pipe up? I'd have unbuckled and walked out the door.
Safety is EVERYBODY's business (ever heard that phrase before?). Just because you have the right as captain to do something stupid doesn't absolve me of the right and duty to point it out.
Honestly, ground should have not allowed him to push back unless he'd de-iced under those conditions.
JH