Let's read what he said:
Darwin explains that the “highest races and the lowest savages” differ in “moral disposition … and in intellect” (36). The idea that white people are more intelligent and moral persists throughout " Descent of Man"... At one point, Darwin says that savages have “low morality,” “insufficient powers of reasoning,” and “weak power of self-command” (97). Darwin’s specific consideration of intellectual capacities is very alarming...He begins with animals: “No one supposes that one of the lower animals reflects whence he comes or whither he goes,—what is death or what is life, and so forth” (62). His remarks soon expand to humans. “How little can the hard-worked wife of a degraded Australian savage, who uses hardly any abstract words and cannot count above four, exert her self-consciousness, or reflect on the nature of her own existence” (62).
"From the remotest times successful tribes have supplanted other tribes. … At the present day civilised nations are everywhere supplanting barbarous nations” (160).
Darwin says that the gap between civilized man and his closest evolutionary ancestor will widen. The gap will eventually be between civilized man “and some ape as low as a baboon, instead of as at present between the negro or Australian and the gorilla” (201).