There was an old adage I once studied at length. "Sins of the fathers will be visited upon the sons." In my experience, it has never failed--in spite of (or maybe because of) Jesus. And here we all are--fussing about the "immigrants." Sweetest of hypocrisy. Frightening for our children.
Is that what the Europeans did when they came to America? Accepted the climate of seemingly endless bounty? And how did the immigrant Europeans rate on the gratitude part? Such musings serve to make many feel better about what our ancestors ultimately committed.
I don't know what you are suggesting "our ancestors ultimately committed," but most of the early European immigrants, who came in relatively smaller groups than the recent pattern, did indeed accept the Settler culture that had created America. Certainly, so long as we had an open frontier, those who didn't like what they found when they first came had an escape valve, other than seeking to change what they found.
But again, for a discussion of the whole question of immigration, see Immigration.
William Flax