The whole carefully orchestrated and built, block upon block, big picture for the Slave Powers was seriously threatened. Lincoln exposed that whole giant conspiracy in his House Divided Speech. He named names, condemned the lot of them from Chief Justice Taney down to Stephen Douglas. It's all right there for those who have ears to hear. He details the long pathway that had been steering the country towards being "all slave". Taney had just made the decision that a black man was not, could not and never would be a "citizen" of the USA.
Of course the narrative of the noble south defending its "lost cause" was later laid on heavily. But there is no way possible to separate the noble and romanticized "Confederacy" from the systematic institution of slavery.
My question to DL would be: Did any free State attempt to independently join the Confederacy? ....... And if so, would they have been independently allowed to join?
But you are correct and I should heed your advice. The man is an outlier and should be cut loose.
It was the loss of that money that caused the Invasion of the South. The intent was to get that money back, not free the slaves.
That "free the slaves" stuff was just the "after the fact" cover story for the love of money that motivated the war.
It's always about money. Always.