@divibisan: You commented on your edit that my understanding of the circumstances surrounding the Civil War might be inaccurate. I'd be interested in hearing such comments (provided they are educational and not bullying) and so I've chosen to revert your edit. Thanks for the concern but I'd rather have such information if it is provided constructively.

I don't understand the problematic part. I'm actually trying to get information. I'll edit out the problematic part if someone can explain what it is.

I edited the OP to make the question more direct and hopefully soften up some of the language used. Please advise if there are further edits which would improve the question.

@divibisan Legally yes. Socially no. As I said in the OP, free speech is a thing in the US so it's impossible to formally abolish the flag, but also as I said, there are plenty of things that are legal under free speech that we don't do because it's not socially acceptable. Why is flying the Confederate flag publicly (both as an entity and as an individual) not one of those things (or, more particularly to the question asked, what are the arguments against making it one of those things)?

@Ertai87 The question recognizes that "What each person does in their own home... is their own responsibility." Is the same somehow not true of cities and states? Can you explain what's different about a city or state deciding this is how it wants to represent itself versus an individual?

@Ertai87 Also not so clear to me is the part about the Nazi Swastika. Do you mean the way it is treated in the United States, where it is not part of our history in the same way? Except for that major consideration, I would say the two symbols are in fact treated in similar ways. Or do you mean the way it is treated in Germany, where the laws and history are quite different?

@Ertai87 And finally, if your question is actually about why the flag is socially acceptable, I'd day that's a valid and interesting question but off topic here.

@BrianZ There is no difference between homes and states except in a matter of scale. In my home, if I want to display the Confederate flag or Nazi Swastika, then I can make that decision with the members of my home and we can collectively decide if that's something we want in our home or not. If we decide we want that, then we can do it. Likewise, if a state wants to display the Confederate flag, then they can do it if the people who live in the state agree. Except in this case it's patently obvious that there is very explosive disagreement about whether or not it's OK...

...and while I understand the arguments of those opposed to displaying it, I don't understand the arguments from those in favor of displaying it. Also I should mention, in general I am in favor of free speech and I would be on the side of displaying the flag, except in this case I see copious reasons to oppose it and no compelling reason to be in favor. That's what the question is specifically about: What are the reasons to be in favor?

@Ertai87 There are neo-Nazi parades in the US quite frequently. Any particular town could theoretically vote to put up a Nazi flag in front of City Hall, and I guarantee you there would be an explosive disagreement about whether or not this is OK, both from dissenters within the town and especially from people all around the country. That's not so different from the reality with the Confederate flag.

So it's still no clear what are you asking for... A rational defense of racism and southern nationalism? Of course there is none.

@BrianZ Right, but in that case the disagreement would be pretty universal, except from the extremists. But it seems significantly more mainstream to display the Confederate flag, and I'm not sure why. Surely there aren't that many people who are just like "yeah, this flag is really horrible but that's ok I'll display it anyway", right?

Like, there's gotta be some other reason for displaying it, and I don't know what that is (and that's what I'm asking about); I've gotten answers containing vagueries like "Southern history and culture" but without details about what that exactly means...

@Ertai87 Why must there must be some other reason besides white supremacy and Southern pride? Why do you doubt that large numbers of people are deeply committed to those things?

@BrianZ Because not everyone in favor of retaining and displaying the flag is a white supremacist (there are plenty of black folks who are in favor of it), and I don't understand what "Southern pride" means.

@Ertai87 Southern/Confederate pride is not that different from all the other regional sub-nationalisms that exist all over Europe and the rest of the world. Name a country and I'm sure we can come up with at least one example of a flag that means a whole lot to some group of people but not others (enough to kill for in many cases, like the Basque flag for instance). The only thing that complicates the Confederacy is its link to slavery and white supremacy. I see no other difference.