Protesters set fire to a photograph of Gillian Gibbons.

Blacks may be persecuted by the Arabs -- or rather, by those who, although they may indeed be black Africans, have been taught, having assumed Arab names and identities, to think of themselves as "Arabs" and thus superior to the blacks whom they are then taught to despise -- but they are also, in Khartoum, Muslims.

Are those depicted in this picture "Arabs" or "non-Arab blacks"? It depends on how they are regarded in Khartoum, and how they regard themselves. Indeed, that tiresome notion of race not existing but being merely a "social construction," if it fits anywhere, would fit the situation in the Sudan. That doesn't mean, by the way, that all black Africans can simply declare themselves Arabs and stop the war being made on them, especially in Darfur. But the clear-cut obvious delimitation between "Arab" and "non-Arab black African" here cannot be made always and everywhere.

In any case, this crowd with the BBC describing it, bizarrely, as "good-natured" -- yes, good-natured screaming for someone's good-natured decapitation -- is united in one thing. They are all Muslims, behaving as they think it right and proper for Muslims to behave, demanding what they think is right and proper for Muslims to demand.

There is nothing else that need, about that crowd, to be said.