Thelio, I wouldn't necessarily say that things like that mean an inherent belief that white people are actually inferior. I think they point to other issues (and that is horrifying behaviour regardless) but they don't necessarily indicate a feeling of "Black supremacy" equal to the phenomenon of white supremacy.
Get used to me. Black, confident, cocky; my name, not yours; my religion, not yours; my goals, my own; get used to me. -Muhammad Ali