Quote - I'm not saying "prejudice is stupid" (although it is) - I'm saying that the statement  "there are lots of black KKK members" is pretty friggin dumb.

It is not, the KKK follows some principles such as:
1- The white race is the superior race.
2- .... blah blah blah ......

Now take a second group that follows these principles:
1- The black race is the superior race.
2- .... blah blah blah .... the same .....

The second group is exactly the same as the KKK

Stupidity also evolves!