By and large, Southern state governments were dominated by the plantation owners who fancied themselves as the inheritors of chivalry and honor. The dominance of the North in the US government meant that tariffs would be raised to protect domestic manufacturers. Southern plantation owners had become quite wealthy due to cheap labor from their slaves and and wanted to buy less expensive manufactured goods from Europe. At the time the South had little industry other than railroads to transport cotton, their main export, to textile mills in Europe. While the Southern secessionist use a lot of rhetoric defending their social order and the benefits of slavery, the real motivation for secession was economic. The ruling class in the South believed that they could conduct business with Europe, and that England and France would provide military support should the North invade.
It is said that all wars are economic in nature.
I do believe that South is not innocent of this matter and I don’t mean to give that impression that they are innocent, but the North was far less innocent and virtuous on the matter than what is taught.