I think people look at it differently when white people do it because it reminds us of a time in our nation's history when African Americans were so thoroughly discriminated against, white actors in black face were used to portray them in very stereotypical ways. Not something we wanted to be reminded of, especially during this time of racially charged politics. While I would agree that it would seem to be a double standard if Eddie Murphy played the part of an asian man, or the Wayan brothers played the role of white chicks, I think the difference is that we have to take a look at the context and times in which they are portrayed. Whereas as now it's more or less done purely for yucks, back in our not so distant past, African Americans were victims of segregation, extreme prejudice, denied civil rights and worst yet, were sometimes brutally killed (dragged through the streets, castrated, burned alived, lynched, etc.) for entertainment. Just look at the graphic images of lynched Black men surrounded by a crowd of smiling white men, women and children. Should we dwell on the past? Did any of us have anything to do with what happened then? Of course not. But sometimes we need to take a hard look at history in order to ensure we do not repeat it. Like 9/11 or the Holocaust, we should never forget.