In this case the contradiction would be mostly avoided by suggesting that minorities benefit more from seeing representation in media than majorities do.
But this just amounts to accepting one of the horns of the dilemma; "Yes, race does matter in terms of representation." And this amounts to a contradiction of the original claim, "No, race does not matter."
The claim that it does not matter has been replaced by a new claim: Asymmetry of racial representation is justified because minorities need it more. However, doesn't this logic seem to validate the obnoxious complaint that "diversity" just translates to the demand "be less white"?
Audiences are generally fine with creating new characters that are diverse, but resistant to established properties being altered (especially if the justification is that race matters). There is always room at the top, but the systemic swapping of redheads, for example, with African Americans does not suggest room at the top, but rather a contest over who will top a hierarchy--exclusion wearing the mask of inclusion, a writing over, a palimpsest of cultural alteration (e.g., not unlike the Christian church appropriating a pagan holiday and making it Christ's B-Day). And if our only answer in light of historical re-writing is "turnabout is fair play," this is a little too close to "might makes right."
The pendulum is always swinging. History is rife with over-corrections. I don't think that there has ever been a time when art has truly been fair. Someone is always getting the short end of the stick. The challenge is not be complacent (fatalism, giving up) and not be chronocentric (that prejudice for the "now" which assumes that we finally have the balance right, unlike our foolish ancestors), but to keep working to get the balance right.