Hiriluk Pirate Flag Destruction Doctor-As-Pirate Doctrine

The flag’s destruction is the chapter’s emotional pivot for Chopper.

Evidence

Hiriluk-as-pirate canonization. The Ch. 142 / Ch. 143 / Ch. 145 skull-and-crossbones = symbol of FAITH / I’ll hoist this flag and fight like a pirate doctrine is now visually paid off: Hiriluk’s flag actually flew above Drum Castle — he was both a doctor and a pirate. The flag’s presence on the castle implies Hiriluk himself had some prior occupancy / claim on Drum Castle (forward-canon: the castle was the old king’s seat that Hiriluk vowed to defend, per the Ch. 145 prison-cell flashback).
Chopper-emotional-pivot to the arc-climax. The Hiriluk-flag-destroyed → Chopper-attempts-mercy-with-Wapol beat is the chapter’s emotional engine; pre-loads the eventual cherry-blossom snowfall over Drum Castle as the posthumous Hiriluk-pirate-flag in a different register (snow as flag).
Costume-prop emblem-match. The skull-and-thin-diagonal-cross flag-emblem matches the X-marked-cross hat Hiriluk wears in the flashback (p. 18) — same emblem on hat, flag, chest-emblem (Ch. 145). Chopper’s pink top hat with the white X is the wearable-version of Hiriluk’s flag.