A commercial company founded by pirates! The incident seems actually pretty typical to me. There's often an element of provocation, a degree of legal ambiguity

A commercial company founded by pirates! The incident seems actually pretty typical to me. There's often an element of provocation, a degree of legal ambiguity, often a degree of moral ambiguity about the laws themselves (extraterritoriality etc). My guess would be that the Nationalists would have seen it as fully within their rights to seize a merchant vessel in China for military purposes. The attack stands out because it comes in just in the tail of the first world war, and it's a naval bombardment of the civilian city of an allied power. It's unlikely (but possible) that a chinese person who had served on the western front alongside the british might have returned home only to be blown up by a british shell! It's also recent enough that it's presumably within living memory for some people who live in the area. It's also an odd time, because at that point, the british and japanese were close allies, and were mentioned in the same breath by the chinese.