Good question, actually. I do believe the song was more than just a 'go australia' deal and more about overselling Australia (e.g. it going on about Vegemite and Australians drinking beer which isn't the greatest of assets), and stuff being ruined by it (the plundering and...well, chundering). From vague recollection anyway... a bit of searching says 'It's really about the plundering of the country by greedy people. It is ultimately about celebrating the country, but not in a nationalistic way and not in a flag-waving sense', so there you go. Yay memory!
We play it often especially on national days (Australia Day) despite the lyrics. It has a fair bit of background - first got popular I believe when Australians won the American Cup (a yacht race nobody else had won before), used for the Olympics, and even had a controversial copyright lawsuit over it.
And I was planning on changing it by my tomorrow the latest, actually, but cheers for asking. Kinda got caught up with a few things of late and also bad internet.