I don't find it offensive at all. Why don't they protest last season's first tribal twist, I could have seen everyone saying that it promotes sexism and ageism. Now this season is promoting Racism? I don't see it.
If anything, it's adding more of the races into a reality show. In previous seasons, they would just have one male and one female african-american, and same for asians and latinos. I think it's just saying that every race has an equal shot at the grand prize now.