The continent of Australia was settled overwhelmingly by people from the British Isles. The people brought their full range of customs, traditions, religion and system of law and government. It was the basis of a new nation that developed and evolved through the decades. Though having its origin in the people of the British Isles, the Australian people in the 1950s were a people distinct from their cousins in England, Wales, Scotland and Ireland. We were Australia. There was no other Australia.
If by immigration our political class changes the ethnic, social and political basis of the Australian population, they will change Australia. Nobody would suggest that China would be improved by an immigration of a number of white people that amounted to one twenty-fifth of the Chinese population and rising. Similarly, nobody would recommend to the Indian people a massive immigration of white people to their continent.