You really don't want to learn any history contrary to the narrative you have been taught, do you?
Apparently they did realize the Union was screwing them economically.
The Southern States now stand in the same relation toward the Northern States, in the vital matter of taxation, that our ancestors stood toward the people of Great Britain. They are in a minority in Congress. Their representation in Congress is useless to protect them against unjust taxation, and they are taxed by the people of the North for their benefit exactly as the people of Great Britain taxed our ancestors in the British Parliament for their benefit. For the last forty years the taxes laid by the Congress of the United States have been laid with a view of subserving the interests of the North. The people of the South have been taxed by duties on imports not for revenue, but for an object inconsistent with revenue -- to promote, by prohibitions, Northern interests in the productions of their mines and manufactures.There is another evil in the condition of the Southern toward the Northern States, which our ancestors refused to bear toward Great Britain. Our ancestors not only taxed themselves, but all the taxes collected from them were expended among them. Had they submitted to the pretensions of the British Government, the taxes collected from them would have been expended on other parts of the British Empire. They were fully aware of the effect of such a policy in impoverishing the people from whom taxes are collected, and in enriching those who receive the benefit of their expenditure. To prevent the evils of such a policy was one of the motives which drove them on to revolution. Yet this British policy has been fully realized toward the Southern States by the Northern States. 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 of them are expended at the North. This cause, with others connected with the operation of the General Government, has provincialized the cities of the South. Their growth is paralyzed, while they are the mere suburbs of Northern cities. The bases of the foreign commerce of the United States are the agricultural productions of the South; yet Southern cities do not carry it on. Our foreign trade is almost annihilated. In 1740 there were five shipyards in South Carolina to build ships to carry on our direct trade with Europe. Between 1740 and 1779 there were built in these yards twenty-five square-rigged vessels, beside a great number of sloops and schooners to carry on our coast and West India trade. In the half century immediately preceding the Revolution, from 1725 to 1775, the population of South Carolina increased seven-fold.
They knew what was going on, but the Union propaganda effort to smear the entire conflict as being solely about slavery has covered up the reality of what happened. The war was about money. Millions taken away from the South, and used to enrich the power blocks of the North.
The Union went to war to keep that money flowing into the Robber Baron pockets of it's masters, and when they realized they couldn't get that money back, they decided to destroy the finances of the South to prevent them from ever being an economic threat to the North.
It was an economic war, with the wealthy New York Industrialists being the beneficiaries of it. We are still being controlled out of New York, but I bet you haven't figured that out yet.