Funny the southerners, in the entire decade leading up to Lincoln's election, didn't complain about tariffs. Funny that the ONLY THING they talked about was slavery; it was the ONLY THING their state legislatures legislated against; the ONLY THING their mail/censorship laws dealt with; and the ONLY THING that their entire religion changed over.
Allowing for the possibility that you have read the debates in Congress for the entire decade, etc., you conveniently leave out of the equation the fact that both the Pierce and Buchanan Administrations were very friendly to the South. They did not have that much to complain of, except the fact that mobs in the North were interfering with Southern rights in some areas, and that the Abolitionist influence was on the rise in the new Republican Party.
It wasn't about slavery per se. It didn't matter what the particular precipitant was. The fact was that the South was being smeared in the North, and in the four way division at the polls in 1860, a purely sectional party--entirely non-Southern had captured the Federal Executive.
If you are not aware of the viciousness of the Abolitionist assault on their fellow Americans, read Daniel Webster's comments on the same: Webster Address. (We quote Webster's speech, rather than a Southern one, because Webster was definitely anti-slavery. But he loved the Union and the Constitutional compact, which respected all the States, more than his personal feelings on that particular issue.)
I do not know why you, as a man interested in history, do not have the decency and kindness to respect those Southern Negroes who were in fact loyal to their States. Why does that bother you? Booker T. Washington also alludes to that fact in his classic speech in Atlanta, 1895: Booker T. Washington Address.
William Flax