Since I'm running a parallel commentary on this discussion, I'll add another comment. :-)
The British comedian Lenny Henry began his career with an impression of Michael Crawford, which everybody was doing in the late 70s, only Lenny Henry did so while black. He also did a TV spot in, oh, the early 80s which began "Hello. I'm Eddie Murphy":
https://www.youtube.com/watch?v=Dath4xOukPs
Meanwhile, Spike Lee's movie
Bamboozled entirely concerns a group of black actors performing in blackface, and what ensues.
Patrick Stewart starred in a race-reversed
Othello in DC, and besides
Carmen Jones, there was a
Black Mikado in the 70s whose soundtrack I have. The movie
Jesus Christ Superstar had a black Judas in 1971, Carl Anderson.
My point being just that yes, all these choices are visibly and appropriately open to art. It's what's done with them that matters.
Cheers,
John