Think as you wish.
Ask those who actually fought, you may be surprised. None at my gun club thinks it's right.
Only a very few. Again, I wouldn't recommend trying to deface Gettysburg (which is taxpayer funded on public land). It won't end well.
Gettusburg is different.
It is a historical park, whose primary goal is education.
I conclude it is appropriate for a historical park or museum to have visual representations of Confederate paraphernalia, if there is a historical context.
I am pretty sure the U.S. National Holocaust Museum has Nazi paraphernalia in it - it does not mean they are condoning the Nazi cause, everyone understands the context is educational.
It is a different matter to place a memorial to a Confederate general on the grounds of a state capitol, or to fly the Confederate battle standard over a state capitol building. Those are public places which represent what the community values. Enemy combatants and enemy battle flags are not appropriate for those kind of community properties.