subject quote from: https://en.wikipedia.org/wiki/Origins_of_the_American_Civil_War

"The war had its origin in the fractious issue of slavery, especially the extension of slavery into the western territories."

From: https://en.wikipedia.org/wiki/American_Civil_War

"I have never doubted what Virginia would do when the alternatives present themselves to her intelligent and gallant people, to choose between an association with her sisters and the dominion of a people, who have chosen their leader upon the single idea that the African is equal to the Anglo-Saxon, and with the purpose of placing our slaves on equality with ourselves and our friends of every condition! and if we of South Carolina have aided in your deliverance from tyranny and degradation, as you suppose, it will only the more assure us that we have performed our duty to ourselves and our sisters in taking the first decided step to preserve an inheritance left us by an ancestry whose spirit would forbid its being tarnished by assassins. We, of South Carolina, hope soon to great you in a Southern Confederacy, where white men shall rule our destinies, and from which we may transmit to our posterity the rights, privileges and honor left us by our ancestors."

From: https://en.wikipedia.org/wiki/South_Carolina_in_the_American_Civil_War

these are just from wikipedia. as someone who professes to love history, i find it disingenuous that you would conveniently ignore the underlying hostilities caused by slavery, and specifically the enslavement of the Africans brought to America, which in turn caused the outbreak of the Civil War. if it wasn't about slavery, there are a whole lot of people on record as saying it absolutely was about slavery, and especially standing in opposition to Lincoln's plan to wind down slavery in the US.