The"racial labyrinth of the 19th-century Old Confederacy"? I'm not really sure what that is/was. However if it is what I guess the author means then he's off the mark geographically and chronologically. Here's non other than Martin Luther King during the 1966 Chicago open housing marches: "The racism and segregation in Chicago is worse than anything I have ever seen in the South. I have never in my life seen such hate, not in Mississippi or Alabama."
The mixing of the races was just as taboo in the North as the South and for just as long- which was right up to the 1960's at least and among some people it is still taboo. Mr. Hanson is old enough to know this.