They're digging up a steamboat that sunk, and they found after the river changed its course. It's super cool. When we went the last time we were driving across the states, one of the guys actually doing the excavating was there. He gave our kids a guided tour and talked about all the exhibits with them. It was super cool.
There were plenty of people who were pro slavery in those days. Mixed all across the US, read Mark Twain. There were plenty of people against it.
More to the point, I wonder if the museum addresses this. I'm going to guess only in a small way, having lived half my life in the south. Maybe someone with actual knowlege can comment instead of web search "experts" like me.
- the Vasa in Stockholm, Sweden is a ship dredged from the harbor and stabilized, sank in 1628
- the Mary Rose in Portsmouth, England is a Tudor ship that sank in 1545 that was raised and stabilized
In both cases a ton of work was done to stabilize and preserve the remains of the ships that is, imo, almost more interesting than the ship itself.