Maybe no one else would be able to teach Aang waterbending without his rubber stamp of approval? He seems to be the top waterbender in the Northern Water Tribe, maybe he can just say to the other waterbenders "Hey, don't teach this kid until he apologizes or I'm gonna introduce you to the worst waterbending swirlie ever!"
LMFAO. Atomic Swirlies. the atomic wedgie can suck it.
Also, yes Pakku seems to be top dog in the NWT. It's not wise to socialize when the top dog has been insulted by somebody.