Ta-Nehisi Coates explains why, in quite simple terms, any comparisons between The Man in the High Castle and the upcoming HBO series Confederate don’t hold water:

It is illegal to fly the Nazi flag in Germany. The Confederate flag is enmeshed in the state flag of Mississippi.

In one conflict, the defeated acknowledged their loss and paid a price. In the other, the defeated quickly got back to their old tricks. 

In other words, imagining a world where the white Southern racist establishment won may not be far different enough from reality to warrant the term “alternate history.”