I have students who think that, because they are not African-American or Latino or Asian, they have no identity. Ethnicity allows for more inclusion. Race is exclusion. A classic example is Israel, where you have Ethiopian Jews, German Jews, Polish Jews, all kinds of Jews. The issue there is ethnicity more than it is race.
Ethnicity is the glue holding that society together.
The glue that holds us together in the United States is that we all perceive ourselves as Americans, though that may mean different things to different people. There is no longer a need to feel as though everyone's got to go into this big stew and become one big mush. Now it's okay to taste the individual flavors of the potatoes, the carrots, the peas. But there is a new taste, too. More and more of them are feeling alienated, hopeless, and scared - that it doesn't matter what they do because no one really cares about them anyway.