I differ somewhat from my fellow Southerners in that I think Lincoln was a sincere abolitionist all along -- from 1854 or 1855. I think his party's platform, of merely excluding slavery from the Territories, was just a waystation, and that he always had the South dialed up for transformation and, if necessary, destruction. He made a moral and political judgment about the South, and when he became president, people started dying like flies.
The South wasn't fighting just to keep slavery. They were fighting to keep from becoming an appendage, someone else's afterthought -- from becoming like the North: venal, loud, brutish and wilfully stupid "morlocks", to use H.G. Wells's word: devolved, subhuman creatures fit only for underground dwelling, dehumanized not just by work, but by habituation to taking orders from economic and political despots, as drones and wage slaves in an empire of sleaze.
Slavery was the key issue that the South left the Union.
That alone makes everything else irrelevant.