In 1970 the Census introduced ethnicity as a distinct category from race, although only allowing a choice of Hispanic or Non-Hispanic.
This was intended to identify and/or conjure up a Hispanic bloc for political mobilization and affirmative action purposes while still allowing Hispanics to claim to be blue-blooded whites. As Lee Trevino explained after winning the 1968 US Open: Now that I’m rich I’m going to stop being a Mexican and start being a Spaniard.
But that has increasingly proven out of sync with the evolution of sophisticated thought among elites (who have now arrived at the intellectually transcendent insight: “White men bad”). So the 2020 Census was reworked to reduce the number of George Zimmerman-like White Hispanics, and it worked: The number of individuals who identified as nothing but white and Hispanic dropped 52.9% nationally from 2010 to 2020.