>>joshua+fh
I don't know what style guide ProPublica uses, but very recently AP decided to capitalize Black when used as a cultural term when it conveys "essential and shared sense of history, identity and community among people who identify as Black". They go on to say that they expect to make a decision soon about whether to do that with "white" as well.
>>jfenge+5j
Capitalizing "Black" is in response to people who identify as Black doing so, I believe. Doing so for people who identify as capital-W "White" would be very different and hand them a victory that will badly distort public debate.
It's amazing how powerful just applying capitalize() to a string can be.