As a caucasian, you dont necessarily understand why something could be perceived as racist because you've never been on the receiving end of that kind of prejudice. So, when the ad is being reviewed there's no one there going, 'uhm, that could be taken the wrong way'.
Race is a pretty tricky topic and if I got into my view on the world, I would be here a long time. Just out of interest, does anyone find this offensive?
Anyway, just thinking out loud.