Let’s take it back to your own words. That a society can’t be multicultural. It can, if by “multicultural” we mean what is commonly understood by that term: that multiple ethnicity groups live together under the same set of laws and political institutions. The vast majority of immigrants to Australia are respectful of our laws and political norms. You’ve blamed immigration for the erosion of liberal democratic norms in the West, but the reasons are far more complex and have little to do with the cultural dilution effect that you seem to be blaming.