I am Australian too and I agree with you, Aussies in general seem pretty open, at least the ones I know. There are quite a few initiatives for mental health like "RUOK Day" where the country is literally encouraged to open up about mental health. Also, I never got a sense that Australians aren't free to express their inner selves. I certainly did and I was always celebrated for it.

This is in Sydney mind you. I have heard places like Queensland and the more rural parts of Australia are more conformist and conservative.