Lot has been written about this. They have always been very selective. I've never been a fan of the NRA because of it. I know several black gun owners, many of whom are open and conceal carry and their view of the NRA is the same. Black guy with gun=thug, white guy with gun=good guy.
https://www.history.com/news/black-panthers-gun-control-nra-support-mulford-act