Yes, absolutely true. We have always been a country that welcomed legal immigrants, and the immigrants were eager to become full-fledged Americans by learning English and otherwise adapting to American ways, demonstrating their unity with their new country.And what "feels right" is manipulating the good intentions and generosity of the American people, who have since their nation was founded have set the modern standard of diversity and inclusiveness. The nation, it's majority population and new immigrants made assimilation a desire. It was not imposed. Often by the second generation, immigrants from diverse backgrounds were proud to be Americans.
Ironically, this more recent campaign of "diversity, inclusion and equity" (DIE) is anything but that. It is an imposed campaign that divides and rejects assimilation, rejects America's traditions, rejects America's majority and, in practice, rejects democracy and capitalism ("equity").
Now, as you point out, it’s the opposite. The Democrats are doing everything possible to emphasize our differences and divide us into all sorts of sub-groups - blacks, whites, gays, immigrants, etc.
It is the very opposite of E Pluribus Unum.