It's a bit misleading to note that Australia's immigrant population is proportionately larger than Canada's. It has to be considered that the two leading countries of origin of these immigrants are the U.K. and New Zealand. In fact, it's my understanding that in general Australia has maintained a fairly significant immigration stream from Europe, presumably because in general the land down under offers superior lifestyle and economic opportunities in comparison to those available in Canada. Australia has in recent decades opened its doors to non-European immigrants and the fact that this has engendered controversy despite the country's broad prosperity suggests that large scale immigration itself tends to be a disruptive process, something its proponents too easily tend to dismiss. Whatever their backgrounds, human beings are, well, human, and as such most don't like change and especially don't like change they view as being imposed on them by others.