I'm interested in the consequences of the delicate response to minority performances. Let's take it as a given that you are perfectly right in the sensitivity of your reaction to how this man's race is being employed. If one feels this way, it seems reasonable to expect others to feel the same way, and that extends to people within the film-making industry. They treat the casting of minorities into roles with this sensitivity; analysing the effect it will have on a post racial world (PRW) (I'd prefer post discrimination world but I'll use your phrase, even though I asked for some expansion on the phrase so that I really knew what you meant by it- can't expect an answer though, I know). The bigger the role is the more delicate the situation becomes. Tarantino uses it the opposite way; the more delicate the situation it might create, the more likely he is to bludgeon the discriminatory point, as if he thinks desensitisation might be the route to take.
So the creators who are sensitive might be less confident with a black lead; knowing a white lead won't present the same delicate connotations to the PRW. The people at the controls of awards might be as sensitive as you are. In fact because they operate an organisation, which by definition has a political aspect, they might be ultra-sensitive. They will certainly analyse a minority performance differently, being sensitive people. They can't possibly analyse it equally with a white performance. They also have to be concerned about the reaction of their decisions out in the PRW press. How could they not be? Being delicate themselves. Also being political, they may not, naturally, court controversy. A white performance becomes, by definition, non-controversial, certainly by comparison to a minority one. And we have a very white looking Oscars as a consequence.
It doesn't look anymore complicated than decisions and actions have consequences. I think it is a personal decision how sensitive one wants to be about any of this, but I think the consequences seem quite clear.