The point about anti-African racism and massacres is a serious one, and something we will undoubtedly cover in Solidarity - to expose and denounce it. We have no interest in prettifying the rebels.
There is also a tradition of racism in Qaddafi's regime, for instance in terms of it's war against Chad in the 80s, not to mention its treatment of migrant workers. But leave that side for now.
No revolutionary should deny that some rebels have rounded up and even murdered black African workers on charges of being mercenaries. It may well be that when some Libyan rebels talk about "mercenaries" this is code for "black".
There certainly are proper mercenaries - including, for instance, even people from the Western Sahara liberation movement Polisario, who Gaddafi has funded. But that doesn't mean there is no racism. (There is a lot of casual racism towards Nubian and Sudanese people in Egypt; Sadat was often ridiculed because he was very dark, etc. Whether or not attitudes have changed, Sudanese and Nubians are still very low on the social scale.)
But does this racism define the rebel movement? It's certainly another expression of the low level of the movement politically. As I say, we must be open about this. But how do you know, or on what basis do you claim, that it's a defining feature?
I've been reading about the American civil war and the background to it again recently. Couldn't you make a much stronger case against support the first American revolution and war of independence on the grounds of the revolutionary leaders' attitudes to black people, slavery and native Americans? This is how the Argentine Marxist Daniel Gaido describes the struggle:
"The American revolution was therefore a hundred percent settlers' affair: it was largely waged against the native inhabitants of the country. The other victims of English colonialism - the slaves kidnapped in Africa - also remained largely indifferent or hostile to the settlers' liberation movement, which is not surprising if we remember that Thomas Jefferson owned over 175 slaves when he wrote the Declaration of Independence... during the Revolutionary War it was the British who, for purely opportunistic reasons, granted freedom to runaway slaves reaching their lines and protected the Indian tribes west of the Appalachians from the spread of white settlement - that is from genocide. In the Declaration of Independence, Thomas Jefferson, the leader of the left wing of the Revolution, accused the British king George III of having "excited domestic [i.e. slave] insurrections among us," and of having "endeavored to bring on the inhabitants of our frontiers, the merciless Indian Savages [sic]..." The Revolution resulted in the establishment of what historians called a Herrenvolk (ruling people or race) democracy, in which immigrants from Europe were turned into "whites" and granted political rights while Indians and slaves were excluded from the category of citizens."
And, therefore, the American revolution was entirely reactionary or insignificant?