There are just no decent logical reasons that it's useful to divide people along the lines of their skin pigments. Even less so to favour different groups on this basis. It's basically ludicrous.
But I'm not sure we should be as hung up on causing offense as we all are (there are too many people to offend, over countless issues, in unpredictable ways). Do we even need this concept if we see the idiocy of racism as it is?
Jeremy Clarkson should be a hero in all our eyes for demonstrating this racism-prat link so delightfully.