The economic logic of what they said is inherently reasonable on it's own face.
It is completely consistent with human nature that people will refuse to be put at a disadvantage economically if they can see a means to avoid it.
Refusing to collect the high tariff would give them an equal footing in trade with the Southern states, so logic implies they would have taken that step.
That all those goods would land in southern ports, get taxed, and then get smuggled into the U.S. in dribs and drabs without exceeding the cost of the U.S. tariff? That's what passes for logic in your world?