Quantrill may have had an ecomonic motive. Lawrence had banks...and whiskey. I don't think John Brown killed with economic systems in mind. Sure economics was there, and religion. These things ovelaid the fundamental problem, the issue of slavery. Slavery in the US stood in stark opposition to the expressed priciples of the founding documents.
Not everyone was as blood thirsty as John Brown. Some people fought to end slavery, but the war was about economics and tax revenues. If a state tried to leave the U.S. now, the same fate would befall them.