Fuck those folks, and I say that as a man with much southern ancestry myself. No one needs to be proud of their racist ancestors.
That's a bit harsh. We're all products of our environments. It's just as true today as it was 150 years ago. How many southerners do you think would have signed up for the Confederacy had they been raised among northern, pacifist, abolitionist Quakers? We're fortunate today to live in an age where we can be exposed to many different points of view if we so choose, and society has advance because of this exchange of ideas. Most people feel more comfortable their own personal echo chambers, but at least today those echo chambers are self-imposed, and not so much imposed by society at large.
Southern heritage is an interesting topic for me. I was born an raised in the South. I have Southern ancestors dating back to at least the early 1700s. As far as I know, none of them were slave owners - certainly none were plantation owners - but some of them did fight for the Confederacy. They probably attended churches whose pastors and sermons were bank-rolled by the wealthy plantation owners. Their politicians were slave owners. I have a hard time faulting them for the side they fought on. I'm not convinced they fought so much for slavery as they did for the status quo. For the life that they knew and were comfortable with. That may make them lazy or closed-minded, but not evil.
I also have ancestors who fought for Nazi Germany. I know their names. I've seen their pictures. I don't know that they were evil. Maybe? Or maybe they, along with the rest of their generation, were simply led astray by a powerful and oppressive regime. Who knows what they could have done with their lives had they been born in a different time or place. But that misplaced potential doesn't make me proud of what they did. And I would no more proudly display a Confederate flag than I would a swastika. But I chose to step outside the echo chamber that I grew up in. This shit is complex, and change takes more time that most of us would like.