It depends. If you're talking about an ancestry that glorifies what those in the Confederacy wanted and stood for, then I wouldn't find it offensive.
Since I don't think anyone here is actually "glorifying" the slavery aspect of the Confederacy, your critique is completely unfounded.
Since you said "it depends," I'm assuming that you would be offended if one's heritage did not glorify slavery, then you are agreeing with my point that he was being "venomous" and disrespectful toward those who respect their heritage.
Full Disclosure: I am aware of one ancestor who had two slaves. That is all I have found on my family tree. I don't "glorify" the man, but see him as a person of his time. I have far more relatives who made their mark on history for fighting and public drunkenness. I don't "glorify" those people either. All of us come from mess-up backgrounds in one way or another.
I don't see a difference either. They were no better than the Nazis. That doesn't make his reply venomous.
There is quite a difference between Confederates and Nazis (as well as the German/Austrian populace and the Nazis), and if you don't know the difference, you are really not qualified to be a cultural or historical commentator on this subject. You are speaking in ignorance and cannot actually address the real issues or history related to this subject. Since you cannot address the real issues, you will not be able to change the minds of anyone who can see through your grade school understanding of the historical and social forces at work in the past and present.
Again we're talking about folks flying a treasonous flag that really came in to being because those Confederate states wanted to keep slaves. And if their ancestors fought for that, I don't have any respect for her ancestors either.
There was a difference between the U.S. before and after the Civil War in terms of how the states related to the federal government. The 14th Amendment - ratified after the Civil War - turned "these United States" into "THE United States. The amendment created citizens of the United States instead of just citizens of states. Therefore, future attempts at secession from the United States would be treasonous. Before that time, it was not a settled matter of law.
Certainly slavery was a major and obvious reason for secession, but it was hardly the only one. Moreover, as I pointed out earlier (but you declined to address), not all slave states joined the Confederacy and the states that did not join the Confederacy were not asked to release their slaves. Even the much praised
Emancipation Proclamation did not free slaves in those areas - or any other areas that were actually under Lincoln's authority!
If the Civil War was truly all about slavery (the North being against it and the South being for it, as popularly thought about the historically ignorant), then the documents of the time would have been significantly different.
Make no mistake... slavery was an abomination and the Jim Crow laws that followed were evil as well. But that justified moral outrage does not justify outright condemnation of everyone who found themselves on the Confederate side.
How many of the people who were not on the Ally side are parading around displaying flags with swastikas on them though? I would venture not many if any because they know what that flag means.
Yes, and even more of them do not because their ancestors hated the Nazis but were caught up in the grand sweep of history.
Where are the folks who feel that their ancestors who participated in that atrocity deserve respect?
You realize that WWII was about more than the Holocaust, right? You also realize that not everyone who was German or Austrian participated in the Holocaust, right? I certainly hope you also know that Hitler and the Nazis were extremely harsh toward their own people and many of them ended up enslaved or murdered because of a perception of disloyalty, right?
It's a completely different situation.