Not to defend Buz completely, I'll get to him in a sec, but Black Islam is a distinct strain of Islam (I believe distinctly American at that). I don't think he meant anything racist by that.
Malcolm X gained fame within that "denomination" as it were, then was killed by them when he split to become strictly Islamic. He had had a religious awakening to the more traditional Islamic culture when on the Hajj, as well as having a falling out with the leader of the Black Islamic community.
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"Civilized men are more discourteous than savages because they know they can be impolite without having their skulls split, as a general thing." - Robert E. Howard