Good grief. Read the various articles of secession where the states lay out their reasons for seceding. Tariffs get hardly a mention.
They are very clear. It is, not just about slavery, but the right to spread slavery to the western states. The American West was the prize.
Not saying I support slavery because I don't. It was an economic issue that caused the Civil War. If the Federal Government had offered to compensate the money invested in slavery to free the slaves in a fair & equitable manner, then succession & Civil War could have been avoided completely.