[infelconi]

The Nation of Islam is a fantastic example but they're tame compared to the Black Hebrew Israelites.

I read the Wikipedia article you linked. Aside from allegations by the SPLC concerning one or two of these religious groups that they preach a form of black supremacy, I couldn't see anything all that bad about it. A bit odd, to be sure, but then the idea that black people are descended from the ancient Jews is really no stranger than the ideas of the Mormons or of evangelical Christians, and seems a harmless form of absurdity.

A little more about one specific group, the Nation of Yahweh, does look a bit nastier. Here's the SPLC's take on the group:

Rebirth of A Nation | Southern Poverty Law Center

So yeah, these are perhaps a bit more dangerous than the Black Hebrews overall, kind of a black version of the Aryan Nations. You seem to have painted with too broad a brush just the same.