Volokh here is decrying the same kinds of policies that I decry, for many of the same reasons. Forcing people into Procrustean categories more narrow than "citizen" for the people of one country builds division in the country and keeps people from treating their neighbors humanely as their fellow human beings. That kind of categorization was wrong and a moral outrage in the days of Jim Crow legally enforced segregation and it is still a bad idea today, even to correct the previous wrong.

I care about this issue deeply. I'm a baby boomer, which is another way of saying that I'm a good bit older than most people who post on Hacker News. I distinctly remember the day that President John F. Kennedy was assassinated--the most memorable day of early childhood for many people in my generation--and I remember the "long hot summer" and other events of the 1960s civil rights movement.

One early memory I have is of a second grade classmate (I still remember his name, which alas is just common enough that it is hard to Google him up) who moved back to Minnesota with his northern "white" parents after spending his early years in Alabama. He told me frightening stories about Ku Klux Klan violence to black people (the polite term in those days was "Negroes"), including killing babies, and I was very upset to hear about that kind of terrorism happening in the United States. He made me aware of a society in which people didn't all treat one another with decency and human compassion, unlike the only kind of society I was initially aware of from growing up where I did. So I followed subsequent news about the civil rights movement, including the activities of Martin Luther King, Jr. up to his assassination, with great interest.

It happens that I had a fifth-grade teacher, a typically pale, tall, and blonde Norwegian-American, who was a civil rights activist and who spent her summers in the south as a freedom rider. She used to tell our class about how she had to modify her car (by removing the dome light and adding a locking gas cap) so that Klan snipers couldn't shoot her as she opened her car door at night or put foreign substances into her gas tank. She has been a civil rights activist all her life, and when I Googled her a few years ago and regained acquaintance with her, I was not at all surprised to find that she is a member of the civil rights commission of the town where I grew up.

One day in fifth grade we had a guest speaker in our class, a young man who was then studying at St. Olaf College through the A Better Chance (ABC) affirmative action program. (To me, the term "affirmative action" still means active recruitment of underrepresented minority students, as it did in those days, and I have always thought that such programs are a very good idea, as some people have family connections to selective colleges, but many other people don't.) During that school year (1968-1969), there was a current controversy in the United States about whether the term "Negro" or "Afro-American" or "black" was most polite. So a girl in my class asked our visitor, "What do you want to be called, 'black' or 'Afro-American'?" His answer was, "I'd rather be called Henry." Henry's answer to my classmate's innocent question really got me thinking. Why not treat all of my neighbors as individuals, one at a time?

And anyway I've seen this issue go wrong for people in other countries. Also in my childhood, in the other state I lived in growing up, I had a classmate in the early 1970s who would get on the school bus each day wearing a button that said "Serb Power." I thought that was very strange, because I knew my history well enough to know that Serbia hadn't been an independent country since Yugoslavia was formed after World War I. And, anyway, he was living in the United States and had been born here, so why was he so concerned about Serb power? We all found out during the early 1990s how crazy many people in Yugoslavia were about former historical grievances, which made that country disintegrate and killed many innocent people born long after the grievances should have been forgotten.

Most reporting to the federal government about "race" and "ethnicity" is based on the U.S. Census bureau definitions for ethnicity and race categories, which in turn are based on regulations from the Office of Management and Budget (OMB), which were announced on 30 October 1997

http://www.whitehouse.gov/omb/fedreg_1997standards

to take effect no later than 1 January 2003 for data collection by all federal agencies. You can look up the detailed category definitions on the website of the United States Bureau of the Census. As the Census Bureau itself notes,

"U.S. federal government agencies must adhere to standards issued by the Office of Management and Budget (OMB) in October 1997, which specify that race and Hispanic origin (also known as ethnicity) are two separate and distinct concepts. These standards generally reflect a social definition of race and ethnicity recognized in this country and they do not conform to any biological, anthropological, or genetic criteria. The standards include five minimum categories for data on race: "American Indian or Alaska Native," "Asian," "Black or African American," "Native Hawaiian or Other Pacific Islander," and "White." There are two minimum categories for data on ethnicity: "Hispanic or Latino" and "Not Hispanic or Latino." The concept of race reflects self-identification by people according to the race or races with which they most closely identify. Persons who report themselves as Hispanic can be of any race and are identified as such in our data tables."

https://ask.census.gov/faq.php?id=5000&faqId=191

It's politics all the way down. I'd be happy to see the United States move in the direction of treating individuals like individuals, equal before the law and all deserving full legal protection of civil rights, period.