The relationship between Australia and New Zealand is very much like the relationship between the United States and Canada. Good friends. Best of friends, really. But there’s always just a little resentment from the junior partner.
Americans don’t care if someone thinks they’re Canadian, but Canadians hate it if someone assumes they’re American. Same thing down under. Kiwis are insulted if someone has the temerity to accuse them of being Australian.
And that explains this Australian tourism video created by a Kiwi. No other explanation necessary.