It's a really interesting story, actually! The question of whether and when to capitalize has been an active one since at least the early 20th century. Here's a (very) recent Columbia Journalism Review article that discusses it from a stylistic perspective:

https://www.cjr.org/analysis/capital-b-black-styleguide.php

And I also thought that this article, about the Brookings Institution's decision to capitalize Black in their reports, had some interesting historical context:

https://www.brookings.edu/research/brookingscapitalizesblack...