i mean others have elaborated on the history thing, but OP clearly means during and immediately after the war. which is think everyone should agree with. the planter aristocracy and slavers in general should’ve been deliberately impoverished. instead they were back in charge within 20 years.
Some do but there are lots that center the voices of the enslaved. Speaking from personal experience, growing up next to a plantation was a really effective way to make it blindingly clear that slavery was a system of massive wealth built on the blood and bones of Black Americans, and make it impossible to buy the lie that it wasn’t widespread or exploitative. They’re important in the same way the auschwitz ruins are