The Civil War was never fought about slavery, and it did not free the slaves. Even Lincoln said so.
Actually Lincoln said quite the opposite:
“These slaves constituted a peculiar and powerful interest. All knew that this interest was somehow the cause of the war. To strengthen, perpetuate, and extend this interest was the object for which the insurgents would rend the Union even by war, while the Government claimed no right to do more than to restrict the territorial enlargement of it.”