[oldE]

"Immigrants! My family has had nothing but trouble with immigrants ever since we came to this country!"
It is true if you marginalize your neighbor, regardless of his race, color or creed, divisions will widen between you.
The speaker seems to bolster his 'arguement' by citing some well known countries with ethnically diverse populations, but I find it hard to think of many countries without diversity. India, The Phillipines, China, Italy, even England have components within their citizenry seeking to differentiate themselves from the majority.
The United States of America is not immune from the ebb and flow of history. As Egypt, Greece, Rome, Byzantium, China, England and others, it is doomed to complete the cycle. Our world is a dynamic, as are the people around us. Very few of us live in the same place all of our lives. Hopefully, fewer hold the same beliefs from cradle to grave. Lines and names on a map are not a country. That honor is held by the unassuming people who toil to feed their families and raise them to be good members of their community.
Les