Number one rule of Zombies: They are everywhere. So wouldn't it have been RACIST to leave out Africa? Also, have you noticed the only people complaining about racism in this game have been white people?
My point being that in RE 4, we were killing Spanish-european people. How come no racism issue was raised there? Now, in RE5, we're in Africa, hense the African zombies.
On a brighter note, the game is amazing and anyone over 13 should give it a go :D