The states with the highest Black populations are also those who have had the most repressive legal regimes since Reconstruction. The white populations have been the most radicalised in terms of their being dyed ideologically "conservative," they are lockstep with right-wing executives, and have been laboratories of experimentation with crushing any dissent.
Any protections that existed federally have been diluted by federal Republicans in the same way - look at how the right-wing Supreme Court defanged the Voting Rights Act, and empowered wealthy fascist benefactors.
Southern Republican governments (as well as near-Western governments like Oklahoma, Kansas, and the Dakotas) are willing to destroy their white populations in an effort to subjugate the Black populations. Look at how they've cut their own education, health, infrastructure systems in an effort to prevent any kind of inequality.
They're the closest places still showing American apartheid - and apartheid is a suicidal system.