http://www.chappelletheory.com/

Although I don’t know enough about this to forge my opinion, I will say that I’ve heard this theory fro a number of sources. Though it is rather dramatic to call this group of figures “the Black Guardians”, the possible motivation and ability of such a group of people do dethrone Chappelle is not at all difficult to suppose.
The idea that this theory was concocted by some “racist white guy” seems more implausible, to me, than the theory itself. Most of the overt racists I’ve met have been simply too naive to know anything more about the people mentioned than the fact they are black, and that they are somehow influential. I will say however, if this alliance really did orchestrate the end of Dave, that a group of really evil guys allowed it to happen. Because there is nothing those bastards like more than to see people argue about benign conspiracies, or argue about racism, while they keep making trips to the bank with wheelbarrows full of money stolen from every race, creed, color, tint, or hue.