It is entirely possible to be proud of the valor and honor of the southern heritage while recognizing that the Confederacy was established to promote an evil ideology.
While the US was not perfect when established, with its unequal treatment of women and allowance of slavery, it did enshrine as a founding principle the essential equality of all men, and by implication women.
The Confederacy, OTOH, was based on a rejection of this principle.
Here's today's fact, restorer.
The South is saving the union from the democrats.
Not one blue state.
And what is evil about States' rights, personal freedom, free trade, and equal opportunity? Oh, BTW, there were both black and white slave owners, there were more slave owners in the North than in the South, the slave trade was based in New England, and Lincoln never condemned the Yankee slave traders, nor freed any slave north of the Mason-Dixon line.
The Confederacy was an embodiment of the ideals and hopes of the writers of the US Constitution. Do you doubt this? Then read the Constitution of the Confereracy.