If there is nothing you can do about a situation, quietude is a coping strategy. Consider the serenity prayer. The word 'serenity', in some circumstances, could be a somewhat insensitive interpretation of quietude or equanimity. But nevertheless the phrase about having the "wisdom to know the difference" is a pithy line.
Note, however, in Buddhism, equanimity is calm detachment. Detached like a calm physician, unflustered, getting on with a life-saving surgery. This is the faux paradox of Buddhist detachment, in that detachment leads to equanimity (upekkha) which helps compassion (karuna), i.e. caring, and taking care of matters.
No one wants a flustered, emotionally overwrought surgeon operating on them; likewise politicians need to be able to be detached (via quietude) while they administer in intense situations. Probably applies in some cold, pragmatic calculus.