Good thing we Yankees never held any slaves. That gives us the high ground. The moral superiority to look down upon those Johnny Rebs. Oh, wait. I just remembered what one of my grammar school teachers taught us in history class. Nevermind.
When the US Constitution declared slaves 3/5 human it was evil. When the CSA constitution celebrated humans as "property," it was evil. Eventually, the U.S. saw the light and officially recognized slavery as evil. What's the argument here?