I think there are other factors at play here. I know plenty of blacks in South Africa who are on expat packages, although they are usually American or British-born blacks. I also know plenty of American-born blacks who are on expat packages in places like Prague, which is far from a hardship place.
I even know Indians on expat packages in Prague. However, I also know people from Poland and Germany who are in Prague on local contracts (although some Germans do have expat packages, or at least used to...the knowledge I have is from a few years ago).