I think multi cuturalism is widely acecpted - but i think there is a big difference between what people regard as sustainable popoulation growth and net migration rate and what the big end of town want/get.
Net migration of 230,000 people per annum os much higher than I think most people would want if they knew the actual numbers. Both sides of politics seem to keep this number quiet and dont want to have to debate it.
In short big business and property developers love mass migration - the average Joe knows it lowers quality of life and increases inequality.
p.s I am talking about overall net migration here - im not concerned with nationaility (I concerned with skills though).
My peference overall is a much smaller and much more skils focussed migration program - with some humaitarian migration to fulfil our international obligations.