I think the issue needs to be balanced.
Jeremy Clarkson is known and encouraged for his outragious views, and his unflinching habit of expressing them - which is fine but,
he is using a publicly funded broadcaster in the early evening to make his views known, when at least some of his audience may entirely miss the skyscraper of hyperbole he likes to build when he opens his mouth.
I find Clarkson an aquired taste, not especially worth aquiring, and i appreciate that his comments were (hopefully!) ironic - although probably not, but that does not excuse the effect of his words.
It is not sufficient to simply say "I was joking ..." and therefore you have no right to be offended - that simply doesn't fly. An extreme example of that as an argument is to say, after running over a complete stranger, that he shouldn;t be bleeding all over the road, because you meant him no harm - it simply doesn;t work like that.
Adults on television have a responsibility to their audiences, and that is not elminated by the desire to indulge in 'plain speaking', or being 'a bit edgy', and then whooping with outrage when not everyone appreciates the view, or the way it is expressed.