Nope. The south seceded just as the colonies did. They became their own country.
They TRIED to secede, but they didn't.
The Colonialists were traitors, but they got away with it because they won the war.
The Confederates were traitors and they lost.
They betrayed the country they were a part of, seceding illegally is treason no matter how you want to dress it up.
You could look on treason positively or negatively.
For example in the Catalan issue, no doubt those who are doing things to get independence are committing treason. That doesn't mean they shouldn't do it. In fact I support their treason.
Nope. They seceded and were overrun by the north. If Lee, et al, had attempted, as americans, to undermine the USA they'd be guilty of treason. But just as the colonials did, the south had established themselves as a nation state and fought to preserve that status.
Firstly, seceding is treason if done without the consent of the country.
So the rest of your fantasy doesn't matter. They committed treason.
I know how much you want this to be true, but the problem is you can only successfully secede from a country IF YOU WIN THE WAR or the other country lets you go.
Catalonia has seceded from Spain, they declared independence. So, why doesn't anyone accept their independence?
Also, the laws of the USA are what are important here. The Confederates were seen as US citizens by the US government and therefore committed treason as defined by the US government.
Since the South lost, and ended up back in the USA, they therefore committed treason. Those AMERICANS who support the Confederacy are supporting treason. Again, there's no way out of this. If a Russia supported the Confederacy, they wouldn't have committed treason. A Russian now who flies the confederate flag is not supporting treason.