I mean yes, obviously: the nation was founded with a giant genocide of native peoples.

I do imagine original white people were perhaps more keenly aware of the fact that this land was not originally theirs, and that other people should be let in and given a fair shot, even if they're poor.

I was merely making the argument that U.S. immigration policy has historically not been very classist (even if it was immensely racist), and not caring about the wealth of the incoming immigrants has worked out immensely well for the country over its lifespan.