The jackleg of no importance that you accuse Kevin of cherry-picking is John Smith Preston. He was a wealthy planter and politician, who was a delegate to the 1860 Democratic Convention and South Carolina's commissioner tasked with trying to convince the Virginia Secession Convention to them in seceding from the Union. He went on to serve as an aide to PGT Beauregard and was later a brigadier general in charge of the Conscription Department. Just because he is not well remembered today does not mean that he was not influential and respected by his peers.
The book that Kevin cites, Dew's "Apostles of Disunion" examines the speeches of those commissioners to the various state secession conventions. It is not a matter of "cherry-picking" quotes, it was an organized and methodical campaign to bring about the secession of all of the slave states.