Let's hear some numbers. How many illegal aliens would you allow into the country? How many legal immigrants should be allowed yearly?
My parents and relatives sure didn't want to leave, but the United States/FDR gave away their countries to Stalin and it was either that or Siberia. Many of my relatives went to the Siberian death camps, and most didn't come back. The rest waited in displaced persons' camps throughout Europe.
At any rate, they were economically much better off before the war than starting over in whichever country would admit them. Welfare and other socialist programs existed here, but there was no way, no how, not one that went on those.
But that was then, this is now, and it's interesting that you think we still need more people in this country. How many more "immigrants" do you think we "need"?