It was ALL about Slavery
Was the Olde Confederacy awful? Of course. None of the rationalizations for secession or “the Cause” hold up under the slightest historical scrutiny. For example, southerners weren’t complaining at all about “states rights” during the thirty years that they dominated the federal government, until 1860.
The secession declarations of each Confederate state make abundantly clear that their cause was exactly and precisely and almost entirely the protection and promotion of slavery. Top middle and bottom. First and last.
The very word is praised more than thirty times in South Carolina’s document. Those who tout any other explanation for the treason know no history.