New Orleans Daily Crescent published an editorial titled "Economic Reasons for Secession" on January 21, 1861. It expressed indignation that the North should be so rude as to object to secession, while the South would be quite happy to let the North secede ("as in common decency they ought to do seeing that they are so unhappy about the countenance the Union is supposed to give to the institution of slavery...").
The writer then explains the reasons that the North is so angry at the idea of secession: because although the South is constantly called uncivilized and barbaric and poor, it is in fact the source of most of the Union's wealth, and secession would deprive the North of the "rich feast upon which they have so long fed and fattened." Since Northerners are descended from Puritans, they have a "love of mean tyranny and cold-blooded, inexorable oppression."
I can quite understand Southerners' anger and defensiveness at the constant accusations of barbarity; no one enjoys being called names even if they're true. However, given that slavery actually was a barbaric institution, the bits about feeding off the wealth of others and cold-blooded, inexorable oppression are painfully ironic.