Tariffs particularly favored the North and their manufacturing plants. By imposing a Protective Tariff on imports from foreign lands, the Northern manufacturers would benefit because since imports from foreign nations, say Britain, were now very expensive, natives would buy from the much cheaper Northern manufacturers. This is what it means to be "protective." It was "protecting" the factories in the North.
The South particularly disliked these tariffs because they did not have any interest in the North benefiting from their money.