If you import cheap labor, you hit your economy by lowering the wages in that sector. When you have immigration, there are a few very top talents and a lot of average people coming, the average ones are not a net benefit in most cases. In US migrants don't create huge problems of integration and culture clashes, in Western Europe there are problems with that so the overall impact is negative.

    > If you import cheap labor

What happens if you import middle class and above labour? In the USA, I assume this is about 75 USD per year salary.