You are comparing two things that are not actually the same. America is the top destination by far for actually skilled migrants who can pump up the economic engine and build highly profitable businesses. America has fine-tuned its entire system to integrate and take advantage of skilled migrants, its tech/research industry being built on this, and its reputation, physical and logistical infrastructure helps to take the cream from the crop.

It's easy to talk about highly skilled immigration when you are the one taking all the best part of it. Those highly skilled productive individuals who can move to America will.

Mass import of unskilled migrants, especially young military aged men, is indeed net-negative, unfair and detrimental to the culture and livability.