I'm an Arkansan, and I consider myself well read on this topic.
Slavery was the popular cause for the war. If you read the resolutions passed by the individual states, most all of them cite the North's abolitionist movement as the reason for secession. In *most* of the Southern states, there was little debate as the the treatment of blacks, or their place in society (as chatel).
Still, slavery was not the *only* cause. The South (and for that matter, Lincoln) did not believe that the federal government had the constitutional authority to ban slavery. When they spoke up to that end, they found the federal government did not recognize their right to secede.
The root cause of the American Civil War was slavery - but the war wouldn't have happened if the federal government had not made it clear that secession would be viewed as insurrection.
This is why I empathize with the Confederacy. Slavery is repugnant, but so is an unconstitutional federal government, which is the legacy we have today from that era. There were other ways of successfully ending slavery, that did not involve killing a generation of young men and permanently polarizing the United States.