During the american civil war, in the south's economy, why did the south feel they were taxed unfairly? (think tariffs)

South Carolina declared unfair taxes to be a cause of secession: "The people of the Southern States are not only taxed for the benefit of the Northern States, but after the taxes are collected, three-fourths (75%) of them are expended at the North (to subsidize Wall Street industries that elected Lincoln)." 

The central idea is that the hiv/aids epidemic is serious.