The flag was accurate for the time, place, and characters of the show and I have no problem with it because TV is fake. I grew up in the deep South and saw a lot of Confederate battle flags and its image on shirts, hats, bandannas etc… until about 20 years ago. I still see the flag around but mostly on backroads and trashy trucks.
We only ever flew the American flag at my house as a kid and still do. The Civil War was an interesting point in history but the Confederacy is nothing to glorify.