General Discussion

Military personnel follow strict customs and courtesies, which include showing deference and respect to the commander in chief and refraining from showing approval or disapproval of political statements. Typical decorum means they are only polite, though the facial expressions of many of them certainly suggested something other than approval.

Kegbreath must have known that the officers wouldn't behave as if they were at a political event, but Trump obviously wasn't expecting a crowd that just sat there and didn't applaud or cheer for him. He's an energy vampire. He's like Tinker Bell in the Peter Pan play who will die if the children don't applaud.