Our country and alliegance to our country is not only about money and therefore an entity solely devoted to maximizing returns. That being said, money is clearly important.
You can conduct whatever detailed analysis you want on the financial impacts of immigration, but you will never be able to convince me that the importation of a largely unskilled, undereducated , English challenged population benefits a country with a vast social welfare state. It doesn't pass the smell test. It goes against common sense.