There is truth to the old nursery songs children sing. This song adds depth to the lore showing that it is know worldwide, and off world just the original meaning was lost, forgotten in time, regulated to a nursery song kids sing when playing. I don't if it was meant to be played up for laughs but when Chuji said not to point that katana at him again Kou didn't even acknowledge it, actually he avoided that conversation altogether, I burst out laughing at that scene. The comedy just writes itself.