The distinction of loci under local adaptive evolution from background selection has been one of the main challenges to evolutionary genomicists. Matthey-Doret and Whitlock (2019) concluded from their simulation that background selection does not affect F_ST severely for the inference of local adaptation. Even though this conclusion is logically correct, the field of evolutionary genomics will be benefited much more if the conclusion were ‘d_ΧΥ should be used to infer local adaptation’.