It's not delusional at all. The War of Southern Independence was a war that was fought for reasons that stretched back to the nullification crisis of 1832, it stemmed directly from a chain of events that began with Calhoun's resignation. And the crisis of 1832 had nothing to do with slavery, it had everything to do with tariffs and it was what lit the spark.
Hmmm. I suppose you wouldn't want to mention the 1833 compromise bill on the tariff proposed by Clay, signed by Jackson, and supported by Calhoun. But for goodness sake, don't mention the Dred Scott decision? John Brown? Popular Soverignty> The Kansas-Nebraska bill? The uproar over whether Kansas was going to entered as a slave or as a free state? Yeah, you better not mention any of that, because if you do, you're earlier statement that the Civil War had nothing to do with slavery will be shown to be clearly delusional.
Sure the tariffs were a hot-button issue and I would grant that they added fuel to the conflict; but to say that the issue of slavery was not a factor in the Civil War just make you look silly.