No, the problem is not that white is inherently bad, the problem is that it is exclusive and does not reflect Australia as a whole. You seem to equate Australian with White Anglo Saxon, and also seem to think that Australia is a 'white' society. This is false, and there is far too much ethnic diversity to label ourselves so. With such a polyglot composition, far from changing 'our' culture to accommodate beliefs of 'others', we would merely be accepting the fact that Australian culture has changed and evolved from one exclusively 'white'.
We are a white society,
At least, I would argue. Ethnicity does not equate to society, but I do believe culture does.
Regardless of how much our culture has changed, we are still a white (Judeo-Christian, to be more PC) society.
Our notions of good and bad, right and wrong, our morality and customs, our political and legal system, our social norms, paradigms and ways of thinking, are all very much elements of a white Judeo-Christian society.
Regardless of how multicultural our nation is, regardless of how many minorities we have or how large they are, they still observe, practice and appreciate the elements that compose the Judeo-Christian society that is Australia.
The liberal-democratic and Judeo-Christian nature of our society is specifically why migrants from all over the world have chosen to be part of it.
And it is extremely unreasonable and unwarranted to change our national symbols because of the idea that we are no longer a white society but rather a non-white one.
Thats not the case because even though our ethnic demographics have changed and even if they change further in the future, our new Australians will still very observe the same white Judeo-Christian culture that existed before them and that will continue to exist even after theirs or other Australian's lifetimes.
Felix