It seems some people have a cartoonish idea of how to present "serious" issues. This also reinforces something I mentioned to my SO who is from South Africa: "I wonder how many people will assume that because the film is based in SO, it is required to be a heavy commentary on Aparteid?"
It's like Americans/westerners have this thing where they stereotype every other culture into like 3 "important" issues and believe every time that culture is mentioned the framework for viewing it has to hinge upon those issues.
District 9 does not need to wave a flag with "APARTEID!" on it. There is this thing called subtle irony. The story gets its message across just fine by demonstrating that everyone, of every race and descent, in South Africa is treating the aliens as second rate life forms - the fact that it is SOUTH AFRICA doing this should be all the irony and on-target message you need. The movie does not need a disclaimer at the beginning that says "THIS IS A SERIOUS POLITICAL COMMENTARY. TAKE IT SERIOUSLY. I WANT AN OSCAR BECAUSE IT IS ABOUT PREJUDICE."