"Sambo" as in "Little Black..." was known and used as recently as the 60s and 70s (see its use in the musical Hair (in case you don't get the context, the racist terms are being decried and satirized): http://www.youtube.com/watch?v=Ovkk7XpOfyo (now, please don't run around calling people the names listed in the song).
"But that was a million years ago!" You say; yep, a lot of people here are quite young. And it's heartening to know that in recent generations, most racist terms have lost their use and meaning--and that IS a good thing.
But I'm sorry to inform you that the Escapist's most frequent users are not representative of the world's population, and not even the entirety of the world's video game playing population. You're mostly very young, and very male (with obvious exceptions; I'm one of them being a woman in my 30s), and I would guess, majority white, and mostly middle to upper class. Your world experiences, I'm sorry to tell you, are a bit limited on certain things, and you are not experts on an issue like this.
But you see, kids--people who were alive back then are still alive now, and there are people who live in areas where certain phrases are still used derogatorily. Some of them EVEN *gasp* play video games!
So there is a legitimate concern here, that someone might get the wrong message from the game. I trust it was indeed accidental, and I don't think the makers of the game should get into any kind of trouble for what I'm sure was an honest oversight (again, thank goodness the word is largely out of use in its offensive role), but it just behooves them to be more careful and do some more cross-checking when/should they produce another game.