You can be proud of your state/region/etc. without being specifically proud of traitor, enemy state... that lasted what ~4 years? People would rightly be upset if someone few an Al-Qaeda, or ISIS flag, or a Nazi flag, etc. The confederate flag, IMO, is no different. Someone can be from the countries these places operate(d) out of, without supporting, these groups.

And to claim that ~4 years as heritage... that's a bit of a stretch. But also, problematic IMO. https://www.merriam-webster.com/dictionary/heritage This to me, implies, these people are still actively trying to trade and own human lives.