Faulty analogy. There is a great difference between standing to defend what is yours from an invading foreign army and being that foreign army while trying to defend your encampment on the land of the people you are trying to invade, as was the case at Sumter.
Leaving out the parts of your argument that aren't true or proven
Specifics please.
Firing the first shot, Toombs warned, would be "suicide, murder. . . . You will wantonly strike a hornets' nest which extends from mountains to ocean. Legions now quiet will swarm out and sting us to death. It is unnecessary. It puts us in the wrong. It is fatal." Sounds like Toombs was right.
Sure he was. Firing the first shot gives a great psychological message to both sides. Unfortunately, that shot had been actively provoked out of the south by Lincoln, so while the psychological damage was recieved by the south by giving the north a cause to fight, that alone does not make the north in the right.
So it looks like the Confederacy was worse than Mao's China or Franco's Spain at least in this respect, that it did not trust to law and diplomacy but chose the path of force, as did Indonesia in East Timor, India in Goa and Germany in Danzig. A bit more patience, statesmanship and foresight and you could have had independence and all the troubles it would have brought between classes and races and competing states and confederations or you could have arranged things within the Union to your satisfaction.
The Confederacy had suceeded in getting most of the federal installations evacuated. They could have existed and built a nation leaving a token federal post intact until a more general settlement had been reached. Given all that it took to defeat the Confederacy, it would be a mistake to think that Sumter and its small garrison posed a real threat to the Confederacy.
But it wasn't to be. Either Davis wanted a war to consolidate his power and pull the upper South into his orbit, or the Confederates were simply betrayed by their own overheated rhetoric, or both. This failure is pretty typical of the movement, for it was always "our sovereignty" and "our rights" raised to absolutes at the expense of other people's rights and freedoms. It was always a crisis demanding immediate action, and never a question of patient work towards a goal. And then when things go wrong, it's the cries of victimization. Those who bait bears or wrestle with lions, shouldn't be surprised if they get mauled.
There is one kind of rhetoric one uses in fighting against a real oppressor, and another that one uses in trying to get a "civil divorce" from a relationship that isn't working. The problem then, and the problem now, is that Southern nationalists have always used the first language -- the language of oppression and victimization and "no alternative" -- when that hardly described their real situation. Defeat in the war only convinced some that the language of victimization and oppression was the right one, and that was exactly the wrong lesson to learn.
In any event, these debates have been going around and around without any resolution achieved or any in sight. Something new comes up sometimes, but for the most part the arguments and assertions are already familiar to all and haven't had much effect.