Since nobody can even agree on whether or not there is anything, intrinsically speaking, that we can call "race" (there isn't... it is a concept that was invented by the human mind), then the use of the word as defined by the dictionary, the place that tells us how words are used, is as legitimate as any other. More legitimate, in fact. The word "race", in the absence of having any intrinsic meaning, means precisely what its use would indicate.