In 1792 under President Washington, a slave owner from Virginia, US tariffs averaged 15%.
In 1815 under President Madison, a slave owner from Virginia, tariffs were reduced to 7%.
In 1830, under President Jackson, a slave owner from South or North Carolina and Tennessee, tariffs rose to 35%.
In 1840, under President Van Buren, a New York Democrat, tariffs were reduced to 13% on average.
In 1850, under President Taylor, a slave owner from Louisiana, tariffs rose to 23%.
In 1860, under President Buchanan, a Pennsylvania Democrat, tariffs were reduced back to 15%, the same as under President Washington.
The original Morrill Tariff proposal, defeated in 1860, would have raised tariffs back to the levels of President Taylor -- about 23% on average.
However, due to Southern opposition, the Morrill Tariff was only passed in 1861 after secessionists left Congress.
By international standards of the time, US tariffs were among the lowest in the world.
In today's world, US tariffs average 1.5%.
So, conclusion: tariffs had nothing -- zero, zip, nada -- to do with the Slave Powers' declarations of secession.
Those declarations were caused by the Slave Power's fears of what newly elected Lincoln Republicans might do at some time in the future to restrict slavery, and reduce the values of their investments.
When the Federalists died out, they were effectively, if not immediately, replaced by the Whig Party (another lineal ancestor of the Republican Party) and Zachary Taylor, though a Louisiana slave owner, was politically committed to the pro-tariff policy of the Northern Industrialists.
The Democratic Party of Jefferson and Madison continued and became the Democratic Party Of Andrew Jackson, Martin Van Buren, and James Buchanan. The Democrats generally championed low tariffs favored by agrarians such as most Southerners.
Taking your tariff numbers for granted without checking them, the only exception in your list to the normal standards was Andrew Jackson (originally from South Carolina and then of Tennessee) with a 35% tariff. I have no knowledge as to why he would be so out of the norm generally and for Democrats in particular. The Bank Controversy? His policy of effectively paying off the national debt which might explain the substantial cut back under Van Buren?
Today's world is utterly irrelevant as to tariff policy. GATT, WTO, NAFTA and all of these infernal sovereignty sapping "free" trade agreements are responsible for today's 1.5% tariff.
I have previously conceded that, since each and every secession resolution recited the "right" of slaveowners, that slavery was certainly A motive for secession. OTOH, there were other reasons and tariffs were among them. Your recitation of tariff history, when viewed through the prism of party and ideology, amply demonstrates that point (except for Jackson).
Your "zero, zip, nada" rhetoric and "conclusion" are certainly not supported by the facts you allege and cite. You may have some supportable argument but I have not seen it yet.
Additionally, very few Confederate soldiers held slaves. So why did they fight if the only war rationale was defending slavery?