u/soggybutter gave some excellent answers to a question about the Black Panther Party a few days ago: https://www.reddit.com/r/AskHistorians/comments/lq0c4b/comment/gofdsfr

Although not the focus of their answer, they mention the fact that the BPP allowed white members, and that some of their social programs helped deprived white communities as well as deprived black communities.