Because they were “conservative”
They do it, in our faces, today. Clarence Thomas, Candace Owens, Ben Carson, etc.
Just like any other “diversity” group - they’re only valid if they’re down with the communist struggle. If you aren’t - you’re NOT that group.
Tl;dr - “y’all ain’t black if you don’t vote for me.”
Don’t forget Thomas Sowell, who I think is arguably one of the greatest minds in America. And sadly, he is also one of the greatest UNKNOWN minds in America, thanks to the progressives.