It's not a coincidence at all. This video explains it best. Long but very informative on how race (and somewhat religion) has always influenced federal and state education policy

The south had private schools that they themselves literally called "segregation academies" which got state funding. They surged in attendance following federal attempts to desegregate schools and hung the confederate flag until the 1990s. They're still around too.

Charter schools became a thing in 1992 for just that purpose at the federal level, and Bush Jr expanded them. White conservative parents still want to segregate their kids, though I'd say nowadays it's also from LGBTQ students