I respect people having pride in their ancestors for their bravery and military service. I also recognize that most people who fought for the Confederacy did not own slaves and were fighting to defend where they lived because that's what people were bound to do. (Although they were not keen on having the slaves freed and living in their midst, an attitude not unusually racist anywhere in the country or the world at the time.)
Because of immigration and migration, your average northerner is much less likely to have a GAR soldier in his family tree and even then very unlikely to know about than your average white southerner and the Confederate Army. Nor were many battles fought here. So we don't tend to take this issue personally and are befuddled when people take it so seriously to the point of hating us in the abstract and blaming us for their past, but whatever, that's how it goes.
What bothers me is when people feel that to defend their ancestors' bravery and courage requires dishonesty about the compromised moral nature of the cause they fought for. I recognize that the north was (and is) plenty racist and many northerners didn't fight to free slaves but to defend the Union or simply to have some adventure. In turn, I recognize that the South seceded over the right of states to preserve slavery, a hateful and soul-crushing system that America is blessed to be liberated from.
Southerners who wish to celebrate their heritage should also recognize and respect the very different feelings the Confederate flag inspires in the many Southerners who are descended from slaves, and consider their region's reputation for respect and consideration when deciding whether to impose this flag on civic institutions that speak for all residents of the state, county, or town, not just the white residents who once were the only residents who counted.
And that's what I think.
By the way, I always get a laugh when someone flying a California flag makes fun of a freeper for living in the blue northeast.