Legendary Italian writer Tiziano Terzani (who travelled extensively across Asia while being a correspondent for Der Spiegel) once said that Hong-Kongers are somewhat like Florentines: they have a superiority complex.
Like the Florentines who, for a multitude of reasons (e.g. having invented the Renaissance, the banking system, blah blah blah), believe themselves to be better than the rest of their fellow Italians, Hong-Kongers believe themselves to be better than the rest and so they think it is important to remark their identity so not to be confused with the rest.
Mr. Terzani was a Florentine himself and was quite ironic in judging this “superiority complex” but still there may be a grain of truth behind it…