The PHRASE "Hebrews to Negroes" aint far fetched (didnt see the film or read the book). The Hebrew 12 Tribes of Israel went into Assyrian and Babylonian captivity and have been lost, with only Judah (Jews) and Benjamin (assimilated into Judah) tribes returning back to the faith and practices (See Ezra and the book of Nehemiah). The other 10 tribes, are not represented globally and their descendants could be black Americans today. There are tribes in Africa ( like the Igbo) who have held onto practices that mirror the Torah for centuries. There are many others, that are not globally recognized.
Judah gets a lot of attention and rightfully so. Its actually from an old prophecy. But Id like to see more emphasis on the other lost tribes Dan, Ruben, Simeon, Levi, etc.
Kendrick Lamars DAMN album was actually about this concept. This is what his cousin Carl was talkin about.