Fixed it for you. The only reason Marx took interest was because Lincoln delivered the Emancipation Proclamation - you remember, the thing that supposedly didn't free any slaves?
You haven't been reading lew rockwell again have you?!
And yes, the Emancipation proclamation didn't free a single slave. How could it? It had no legal effect in the states that were governed by the Confederacy (just like our government wouldn't be effected by an executive order issued in Britain). And it didn't free the slaves in the northern states. It specifically said so. It also specifically said that slaves in union held territories in the south were also exempted from freedom. So which slaves exactly did it free? And why was the 13th amendment still necessary?