As wacko as the Left's narrative of the Civil War is, the Right's is just as crazy. Between the Communist co-option of the Union and the identification of the Confederacy with Nazi Germany (and the subsequent adoption of the Confederacy as the Conservative Republicans of their day) the actual history behind the Civil War is being banished to an Orwellian memory hole.
The Slave Power didn't believe in states' rights. They just grabbed that slogan once their conspiracy against the Free States failed and a non-extentionist was elected President. What a reason to leave the Union and start a war!
I think it is reasonable to point out that the CSA had a key ideological issue in common with the Nazis. That is the idea that there is a Master Race and slave races.
While the two systems were very different, it’s not difficult to imagine the CSA, had it won, developing in a direction similar to that the Nazis later followed. Once you really believe in a Master Race ideology, a lot follows logically.
I guess you are unaware of Virginia's contribution to Independence from the English Union.