Clearly I'm not as politically correct as liberals. While I denounce Jeremy Clarkson's unfunny attacks on the national character of Mexicans, I'm not quite sure that it is precisely racist to talk about your TV reception as being "like Lenny Henry in a cave". It isn't exactly polite and it's certainly not amusing, but it says nothing derogatory about being black. Perhaps there is a pre-existing sensitivity to the fact that he has a mouth on him like Prince Philip.
I also fail to see why Lars von Trier has been banned for life from Cannes. There seems to be certain conditions for joking about being a Nazi and Lars didn't meet them, despite saying during the actual speech that he was aware that Hitler was "not a good guy". It may not have been smart, it was hardly deftly handled, but it's not as bad as the Michael Richards and Mel Gibson rants, which were said without humour, and designed to offend. And, as one reporter noted, Roman Polanski committed an actual crime, and he's not black-banned.