i dont think people should use prosthetics to look like real people in biopics, period. it's a dumbass idea even when there aren't racist connotations.
I always think back to that one Nixon biopic as an example of a believable portrayal having a lot less to do with if an actor looks like the real life person and more to do with their acting skills. I can't remember which Nixon movie it was, actor might have been John Goodman or something, but they nailed Nixon's affect and mannerisms perfectly.