Marxist biologist, Stephen Jay Gould, was among other things, a critic of racialism, at least as it related to claims that supported some sort of positive conclusion about Whites. I could not find, for example any work critiquing say East Asian IQ superiority, although he could have written on it, I did not find it.
But one claim he did make in his 1981 book, The Mismeasure of Man, was that Samuel Morton, who measured hundreds of human skulls in the 1830s and 1840s, concluding that the brain volume of Europeans was greater than that of Asians and Africans, was a “patchwork of fudging and fingling in the clear interest of controlling a priori convictions.” Ok, he was a racist, just doctoring data, the same way we might see today, the Democrats doctoring votes. Only, he was not.