They did exist for decades, the South grieved them over and over with result. That’s why secession was their final recourse, it wasn’t their first choice.
It was not ALL about slavery, that simply helps you justify the US actions. It’s what simple minded people accept actions they know are wrong, the ends justify the means.
The North would’ve took up arms if slavery wasn’t involved.
The tariffs in question, which weren't between the states, rather on goods imported to the US, did exist for decades, and were slowly being reduced to satisfy the South. When the war started tarriffs were at a ~ 25 year low due to the efforts of Southern congressmen chipping away at them (see: Nullification Crisis - when one state deemed tariffs unconstitutional, rather than seceding). And the South obviously wasn't opposed to the idea of implementing tariffs since they levied a 15% tax on any goods imported into the CSA, including those produced in the USA.
And yes, the Great/Missouri Compromises in the first half of the 1800s, to which I was referring, solely addressed slavery.
I'm not saying the North fought this war to end slavery, I'm saying the South seceded primarily because of, then fought to maintain, slavery. No slavery, no civil war. I know it, you know it, leaders of the CSA said it. It's the truth whether you want to mask it behind the weak excuse of tariffs or not.