The five-dot flag is set ablaze and the horrified silence gives way to the flood of disbelief that follows; Spandam's obvious panic spreads to his subordinates, festering pandemonium in seconds.
In contrast, the Straw Hats stand stony-faced and silent. And Chopper, whose hearing is still sharper than most in his human form, doesn't miss the stricken question.
"Does he even understand the meaning of attacking a flag?"
Chopper doesn't understand Luffy, doesn't pretend he can. His captain is a strange balance between boundless freedom and ferocious loyalty, the epitome of chaos and clarity; Luffy wears despair down into hope, strips impossibility down to fact – and then tilts his head like he can't fathom how anyone could have missed it.
This and this alone, though, Chopper knows: Luffy, the same man who had shielded a lonely reindeer's flag from a king, ordered to burn down another's. That order isn't the jest of a child or the bravado of a boy; it is a precise attack and the rage of a pirate wronged.
You took what's ours, Chopper agrees with an exhilarating rush of fury and love. Now we will stop at nothing to get it back.
He stands taller, calmer than he's ever been, fearless in a way he didn't know was possible. The world can buzz all they want that Straw Hat must be insane; Chopper knows that there is method in madness, that Luffy is a straight line in a world drowning in curves, the one path Chopper will trust and follow even into war.