Interestingly you might get a very different answer to that question in Brazil than you would in the USA. I saw an interview with a Brazilian footballer that looked black to Americans sounding surprised when asked by an interviewer asked how racism affected him. His answer was, paraphrasing from memory, “what are you talking about I’m not black.”

Meanwhile race in the USA is of major political importance. It matters for college admissions, government loans and contracts, and so on. By and large it’s on the honor system. So far at least there haven’t been many white presenting Americans identifying as black or mixed race when their DNA test shows 4% African ancestry.