Oh yeah I guess I heard all this, I've never debated with "lost causers" myself lol the ones I'm mainly talking about don't actually know any details to even try, they just scream "states rights" on cue
States Rights is their only real talking point tbh.
They even try to debate the idea of Slavery finally dying out within a few decades if the South never succeeded, but the issue with that is this:
The Cotton Gin made it so the economy of the South was so lucratively dependent on Cotton that slaves still would have stuck around during the industrialization of places like New Orleans, Atlanta, Dallas, and San Antonio. First off, they're slaves, you don't have to pay them, and industrialization would have actually made them an even cheaper to house than in Antebellum Southern days.
Slavery was simply never going to go away.