Are you familiar with the history of blackface in theatre and film?
No, we are not. Untill the jackson 5 thing I had never heard of blackface, and I still cannot see how it could be considered "racist" to be honest.
To me, painting your face black to be in costume as someone who is infact black, seems like nothing but a sensible decision. I mean, the costume wouldn't make much sense if you had white skin, same as it wouldn't make much sense if they didn't put the wigs on.
I think people need to just chill out. I mean, was anyone genuinly offended? If anyone was, I am sure those in costume are very sorry and meant no offense.