No doubt there are truths in everything said, some will be illiterate, some will be a drain financially on the system, some will contribute and work, some will start businesses and be successful.
My perception is that we have to much migration and we do not need a big Australia.
The countries that have the highest standard of living and highest satisfaction living rates are the northern Scandinavian countries
who have very low population growths; low migration rates and sustainable economic models