Lincoln was wrong. Slavery existed through a lot of the western territory mostly by 5 "Civilized" native American Tribes."Nobody went to war over what a rebellious people called themselves."
So we should stop all attempts to label the people of one time with the calling card of another and just accept the fact the two rebellions were no where alike.
"...One eighth of the whole population were colored slaves, not distributed generally over the Union, but localized in the Southern part of it. These slaves constituted a peculiar and powerful interest. To strengthen, perpetuate, and extend this interest was the object for which the insurgents would rend the Union, even by war..."
Abraham Lincoln, Second Inaugural Address, March 4, 1865.