I haven’t heard mulatto in some time, but you are correct. It used to be used for mixed blacks. In any case, I think the current term for American Blacks is “mixed”. I’ve even heard “yellow”, I think.
But in Kamala Harris’ case, she is simply not from an American Black background. Her mom was Hindi, her dad Jamaican, and probably with some African in his background. They came to America and did not claim citizenship until long after Kamala’s birth. Both were connected to university jobs, I think. Got divorced.
Harris spent her crucial formative years in Canada from about 12-18, iirc, because her mom moved there.
There is nothing about that background that touches the background experience of an American Black.
My primary care physician is from India..no way would I classify him as black...He just isn't.
Fish gotta swim, birds gotta fly,
I'm jus' a Dem, so I lie and I lie,
Can't help towin' the race card line...
If Kamala’s parents are naturalized citizens, does that not make her ineligible for the presidency?