Facebook can definitely figure out your race , and the race of who you've dated.
I told this story here before but back in the early days of facebook, I had dated a Korean girl for a brief period of time and then the moment we broke up via facebook messenger, I start getting spammed with ads for dating websites featuring Asian women ( maybe the algorithm wasn't advanced enough to figure out my ex was Korean specifically).
I think a lot of this is just posturing, I don't see Joe Biden being as harsh on social media as Trump has been. This might be a final hurrah against social media as conservatives have been very upset with them lately.