So, because they said, "We're going to commit treason," before they did it makes it not treason? Sorry, but allowing unilateral opt out of government by any individual or group makes government meaningless. So, saying, "You're not the boss of me!" first doesn't alleviate the charge of treason.
I've got to say, I hate the idea that if you join the US you, it's eternal on pain of death. I'm pretty much universally for the devolution of powers and rights to smaller political entity. Just look at countries ranked on the wellness and happiness scales. People have far greater trust in government institutions in smaller countries.
I believe states should be able to secede, regardless of reason. I'm not saying the southern secession followed a good protocol in deciding when to secede, but I think you would be very surprised if you actually read some of the history of how the transition took place. Think about everything that has to switch over. The federal government was far less monstrous 150 years ago, but courthouses, judges, tax officials, military installations, etc, all had a transition to go through. Many were very straightforward. Courthouse employees came to work one day as US employees, the next as Confederates. IMO, once the secession took place, the view of the north was the treason already occurred.
Short version: treason can be a justified rebellion if the state is committing crimes, it's just treason when done to continue committing crimes.
No, completely wrong. Treason can be justified IF YOU WIN, in which case, it's no longer treason.