Actually it indicates that none of the Southern leaders, from Robert Lee to Jefferson Davis to anyone else you care to name, didn't believe that slavery was a dying institution. Texas was pretty blunt about what they thought about the future of slavery in their Declaration of the Causes of Secession: "Texas abandoned her separate national existence and consented to become one of the Confederated Union to promote her welfare, insure domestic tranquility and secure more substantially the blessings of peace and liberty to her people. She was received into the confederacy with her own constitution, under the guarantee of the federal constitution and the compact of annexation, that she should enjoy these blessings. She was received as a commonwealth holding, maintaining and protecting the institution known as negro slavery-- the servitude of the African to the white race within her limits-- a relation that had existed from the first settlement of her wilderness by the white race, and which her people intended should exist in all future time" That was no doubt the consensus throughout the South.
Nonsense. Good try though. You can’t have it both ways.