Yes, so much is causational, connected and nuanced with every rule having so many exceptions. Even most of our best science is not the truth just our best explanation for what we have observed with a pursuit of better explanations to get closer to the truth. You can say it is our brain that seems to prefer binaries but it more our nature, our laziness, our desire for simplicity, it is our psychology, sort of our brain.
Be careful using Anglo American in place of Caucasian. Most Caucasians in the U.S. are Anglo but not so world wide even if you don’t include Hispanics. We have Nordic Americans, Scandinavian Americans, Italian Americans, German Americans, Greek Americans, Slavic Americans………..I am Anglo, my Wife is Italian American. Don’t forget about Jews, Turks, Pashtuns, Uzbeks, Arabs, Persians and etc. when counting Caucasians.
Where I live right now there is a strong Acadian Culture which is very interesting to me, you see the Acadians were kicked out of Northeast America (where I grew up) and sent back to France where they were not welcome and were send back to America to resettle in Louisiana (where I live now) which at that time was still controlled by the French. The Cajuns are decedents of the Acadians and they live in the Acadiana parishes on the Gulf Coast.
While it is not officially recognized it also includes the adjacent parts of Texas and this is the part of the world being troubled by a hurricane right now.
I wonder if Black Americans are not a more homogenous culture than White Americans. Do Black Americans not see how White America is such a diverse culture with big regional differences (I am not saying that we are not amazingly privileged and racist but we are different). I am sure everyone can tell a Cracker from a Yankee but some of the differences are subtle. I know I am blind to most of the cultural differences in Black America. I know my Black Studies are very weak but there have been social ranking among Black people in America for centuries some of the categories are the Decedents of Free People of Color, the Decedents of Slaves and the High Yellow who might or might not be the Decedents of Slaves and of course there are more recent Black Immigrants.