Though economic factors have historically provided the impetus for wars, I am unconvinced by your one-sided logic. Certainly, slavery was an important economic factor in the South. The constitution of the Confederate States made the protection of slavery a central theme. The major political battles in Congress throughout the first half of the 19th century were centered on promoting or prohibiting the spread of slavery into newly admitted states, not for primarily moral reasons, but because they could swing the political balance in Congress and because slave populations impacted representation.
Were tariffs and taxes a major contributor to the tensions between the regions? Almost certainly. The impact of abolition on Southern agriculture would be (and ultimately was) catastrophic, Were tariffs and taxes the primary cause of secession? The political rhetoric of the 1850s says otherwise.