I guess to me, “ancestors” could be a lot more informative. If you look like you have a South Asian parent, that could mean that parent was born in Vermont, but their parent was born in Scotland, and their parent was born in England and their parent was born in Chennai. And those are the stories I love to hear about because they’re kind of like my own ancestry. For example, my great-grandfather was the son of a Polish emigre to England, moved to Germany, had a child with a German woman, he married a woman from England with parents who were from Russian and Poland and he emigrated to London, and they had my father, who emigrated to America and married a woman from New York.
And if I just ask their ethnicity, I don’t get the story, which could be far more interesting than the ethnicity.
Just with Kamala Harris- knowing her father is black is a lot less informative and interesting than knowing that her father is from Jamaica, which itself is less interesting than knowing her father himself is multiracial because his father had a European parent (and, of course, knowing that he’s a world-renowned economist is very informative too). And that’s why I would like to know about family history much more than just ethnicity. But those can get mixed together.