Exactly backwards historically.
In the late 18th and early 19th centuries it was, among educated men at least, accepted nearly universally throughout the South that slavery was evil and must ultimately be gotten rid of.
By the 1850s this had completely turned around and slavery was (almost) universally accepted as a positive good that should not only be preserved but expanded. In fact, the newly elected veep of the CSA made this the main point of his most famous bit of rhetoric, the famous Cornerstone Speech. In it he explained why Jefferson, Washington and all those earlier southerners who had believed slavery to be immoral were wrong. Human inequality, in its ultimate form - slavery, was to the the Cornerstone of the CSA, rejecting and replacing the USA's Cornerstone of human equality expressed in the Declaration of Independence.
If you accept, as Lincoln did and I do, the DOI as the best expression of what it means to be an American, the Cornerstone Speech proclaimed a declaration of war by the CSA on the very concept of America.
Stephens' speech was widely plauded throughout the South. In fact, I have never come across a single expression of disagreement with its basic themes in any contemporary southern document. IOW, he expressed the conventional wisdom of his society.
http://www.nationalreview.com/corner/262624/confederate-cornerstone-richard-brookhiser#more
You make a good point, but I'll take recourse to the observation that men defend most violently, not the things they know to be true, but those they fear may be false. Lincoln believed that the Negro race was inferior to the white race, but as he said in response to Steven Douglas, “In the right to the bread, which she has by her own hand earned, [the Negress] it the equal of me, of Judge Douglas, of any man.” Secession was the death throes of a moribund system.
What you do not acknowledge is that it was a "rabble rousing speech of interesting historical note" given by a highly eccentric politician who also happened to actively oppose secession throughout the entire process of his state and who had no role in the confederacy's formation until after Georgia seceded against his wishes, at which point he sided with her and altered his position to one espousing the new southern government.
To treat Alexander Stephens as some sort of rabid secessionist leader who held the key to the confederacy and all the movements that brought it about is an abusive and unhistorical telling of events to its very core.
"If you accept, as Lincoln did and I do, the DOI as the best expression of what it means to be an American, the Cornerstone Speech proclaimed a declaration of war by the CSA on the very concept of America.
That is the same type of self-righteous hyperbole that Stephens used in his speeches, and did nothing to restrain the outright venomous hostility that pushed the Union into war against the South.