I wonder if they include the removed portions of Origin where Darwin says Africans are a lower evolved, lesser species.
Darwin says,
“at some future period ... the civilized races of man will almost certainly exterminate the savage races of the world. The anthropomorphous apes will no doubt be exterminated. The break between man and his nearest allies will then be wider, for it will intervene between man in a more civilized state, as we may hope, even than the Caucasian, and some ape as low as a baboon, instead of as now between the Negro or Australian and the gorilla.”