Many Americans consider themselves to be Swedish or Italian or Polish because of where their grandparents or earlier were born, but are they really? I have four great-grandparents born in England and four who were born in Germany or in what is now Poland.
But I do not consider myself English, German, or Polish. I consider myself American. I grew up here, my parents grew up here, and my grandparents grew up here. Actually one grandmother was born in Schliesen, now part of Poland, but she went to American schools all her life.
When I went to England, I was not English, but a Yank. When I went to Germany I was not German, but ein Amerikaner.
We will continue to have people from elsewhere come to the U.S., settle, and adopt many American ways. Some will keep customs of their parents or grandparents; others will blend in. Some will keep their religious views; some will change. Consider the Amish. Although there may be hostility to them by some, they are accepted by most people. Can't we treat all newcomers with the same respect?
Oh, it gets more complicated. My extended family includes people whose ancestors were born in Japan, China, and Africa. I consider all of these as Americans first, and whatever as a matter of historic interest.