The southerners (I'm not one, I was born in Wyoming) had many gripes about the way the north treated them, such as representation in Congress and tarriffs on goods that were produced in the south and shipped north. In their view, the north had the most say on how the rules were written and they felt that the north was writing the rules to be rigged in their favor at the expense of the south.
1. I like to root for the underdog
2. I like their uniforms
3. Their Generals had some colorful names: Beauregard, Stonewall, J.E.B. Stuart, Longstreet.
However: it's quite clear that without slavery, the war would not have happened.
The other issues - states' rights, tariffs, homesteading, territorial organization - would have created friction for the young republic, but without the prism of the slavery issue, they would have been addressed without resort to war.
All conservatives and libertarians - let's be fair here - are concerned with the power of Leviathan. I think for many here the Civil War has become a handy anchor for tracing the growth of Leviathan and the deviation from the Founders' Great Design.
I understand the impulse. I just think it's misplaced.
I quickly and readily concede that Lincoln played fast and loose with the Bill of Rights and the Constitution and oversaw a great expansion in the power of the central government. Yet two other realities stand out: 1) the same phenomena were just as apparent (if not more so) in Jefferson Davis's government (thus illustrating the truth that nothing aggrandizes government power in the modern era like full-scale war), and 2) the growth in federal power was sapped in the postwar era by business tycoons and anti-reconstruction southern Democrats.
It would not be until the early 20th century - beginning with the 16th amendment in 1913 and then the explosion of state scope and power necessitated by two world wars and FDR's New Deal - that Leviathan returned. Only this time it was for good.