The term "people of color" endorses a racist outlook towards humanity by treating "color" as as a matter of essence, of the substance a person is made of, rather than as a superficial detail.

The distinctions we call "racial" are grab-bags of various details, each of which correlates more or less with certain ancestral groups. They are real differences, but not particularly important unless people make them so. So let's avoid using essentialist language to refer to them.