the liberal-democratic society is founded on egalitarianism being true and good unquestionably. if all people aren't equal and all the same genetically (and as a result, racially), then it would be absolutely illogical to treat those who are measurably worse the exact same as those who are measurably better. so instead of proving egalitarianism as correct and good by validating that there is absolutely no difference between the races (which they also try to do but in certain cherry picked situations like saying mitochondrial dna is pretty much the same thus our differences are all superficial), they choose to invalidate areas of study which could prove egalitarianism to be stupid and wrong. it's because they are not actually in search of truth, because the truth is dangerous to the philosophy they base their entire lives and societies on.
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