This should earn him an Academy Award, now that Halle Berry has opened the door for him.
I used to think the people who said this meant that you had to be African American to relate to the "black experience" to be able to understand -- which of course is stupid. (The word "empathy" was invented for a reason.) These days I can only surmise that what they (being the people who say this) mean is that these "African Americans" are saying things to each other that they don't say to other races -- in other words, it's a "secret thing" -- and only the black folks who say "you have to be African American" are the ones in on the secret.