I think you will find that the descendants of immigrants who suffered unimaginable trauma have not "gotten over it," either - they just know America is not responsible for that trauma, so they don't have anything to demand of America. (In many cases, the political entity that enacted that trauma is effectively no longer existent, so they have no one to make demands from and they have gotten as close to justice as they ever will; in many cases, America was directly responsible for that happening, so they certainly have no reason to feel like America owes them anything.)
I'm specifically referring to the people referred to in the comment I was replying to, i.e., immigrants who fled trauma in their home countries and became successful in America.
I agree that there are also many cases where America did inflict trauma on immigrants, and they can rightly hold America responsible in such a case. But that's not what the person I was replying to was talking about.
