Let's not point the finger and let this discussion degenerate into a race-based discussion. We all know that there are impolite people from all parts of the world.
Sorry, but I have to defend the original poster here. There was nothing "race-based" about that comment. Hong Kongers can be some of the rudest, most impolite human beings of any major city. Behaviour that is either tolerated or even deemed acceptable here is frowned upon in pretty much every other major financial centre. It has nothing to do with race--it's an issue with this city, and its culture.
I understand your role as a moderator, and if this was after a series of multiple comments I would understand, but the original poster's comment, particularly as a one-off, was completely fair, and in no way racist.