It is a symbol of rebellion.
It wasn’t freshly designed for the Confederacy, though.
GENERALLY
When the Dixie flag has flown over Democrat reign, it has marked infamy and mischief
When the Dixie flag has flown over Republican reign, it has marked healing and progress
Against being forced to free their slaves from their oppression.
Quick Take on Civil War:
Suppose for a moment that the Federal government wanted to pass laws and enact policies that effectively removed the individual right to bear arms.
The Feds and particularly a new presidential candidate let slip their plans to turn Puerto Rico, Guam, Northern Mariana Islands, US Virgin Islands, and American Samoa into full states with voting Senators and congressmen.
In exchange for Statehood and other cash payments (to the right causes and people) these new States would tip the balance of power enough to meet the gun control objectives.
Getting wind of the plan, first, the constitution respecting States object, but then after losing the election they see the wheels go in motion, call their respective legislatures, and vote to secede.
Did they vote to secede over gun control? Yes, to some degree, but at least as importantly, they seceded because the Federal government was acting outside its authority, and taking action to unfairly change the balance of power to pass new law.
Do the people in the seceding States have a right to pride in their stand? Whether one agrees or disagrees with gun control, it is perfectly fine to have pride in those that stood up to the Federal government power grab.