Maybe he gets it from here; you’ll see a certain familiarity with the arguments we often see from the hard core South haters:
http://www.marxists.org/archive/marx/works/1861/10/25.htm
http://www.marxists.org/archive/marx/works/1861/us-civil-war/index.htm
I had realtives on both sides and they all fought in the Trans Mississippi West and at the battle of Prairie Grove, against each other. Great family stories and I’ve managed to get records of my Confederate Great-great grandpa.