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.
I made no such claim, and I'm fully aware that Stephens, and for that matter Davis, opposed secession up to the point where it became inevitable. The true fire-eaters, such as Slidell and the Rhetts, were pretty much excluded from office in the CSA, the politicians being scared of their radicalism. Davis and Stephens were known as conservatives, in the southern tradition of the time, of course, which in my opinion is diamatrically opposed to true American conservatism.
Which actually adds to my point. Even those who were not originally in favor of secession accepted as a matter of course that slavery should be not only maintained but also extended, that it was a positive good. That human inequality should be the basis of society, not human equality. IOW, as I said, Stephens expressed the conventional wisdom of the South at the time.
If you disagree, feel free to point me towards the public speeches and editorials that disagreed with him at the time. I always appreciate being shown where I have misinterpreted history.