The answer is simpler than you may imagine: how threatened?
The fact that you are skipping right over an answer to "x's" question, and going straight to your argument that it wasn't being threaten implies that you agree with the premise that "x" has put forth. (That threatening slavery would be regarded as a tyrannical act on the part of people who's thought it was essential to their society.)
So you give us an implicit "yes", to the question, else you would not try to immediately defend the claim that it wasn't being threatened.
Apparently it was, because when Lincoln had the chance, he ended it. Now you may argue that was because he wanted to put the screws to people with whom he had just fought a war, but can it be doubted that absent a war he would have thrown up every sort of "executive order" restriction on it that he could have managed?
He would have used his power of the "Pen and Telegraph" to interfere with it in every manner that he could possibly could, and I expect this was exactly what the people of the South perceived about him.
Would he have interfered with it in all manners possible? The People of the South thought he would, and when he had the chance, he did in fact do this. So were their fears of him unfounded? Should they have ignored their own impression of the man and simply trusted him?
I think they accurately perceived him as a serious threat to their institution, and therefore they perceived him as a threat to something they considered essential to their society.
So to go back to "x's" point, someone threatening what you regard as essential to your society creates a just cause for revolution.
If it's purely subjective whether a right to revolution exists, it's subjective all the way around. Your subjective assertion that your rights are being violated conflicts with my assertion that they aren't and the result is war. That's the result of radical subjectivism in politics.
But it's not even that your "rights" were being violated, it's that you think that they might possibly be violated some day. That doesn't sound like a real rationale for revolution or rebellion. There was something opportunistic about secession: the leaders were trying to exploit a momentary panic. They weren't committed to working within the nation, but were using the emotionalism of the moment to enhance their own power.
Moreover, Lincoln knew and was friends with Alexander Stephens. He was in Congress with Stephens, Toombs, Cobb, and Rhett. They knew him. They knew what he was like. They knew that the hysteria about Lincoln's election didn't reflect what the man was actually like. They knew he wasn't a true abolitionist. But they chose -- for whatever reasons of their own -- to go along with the hysteria and promote it, rather than discourage it.
No he didn't.
Not at all.
In fact, slavery was first "threatened" then legally abolished in every Northern state during the early 1800s.
Different abolition processes were used in different states, from passing new laws to state constitutional amendments, and everyone understood that slavery nationwide could only be abolished by US constitutional amendment.
By definition, the US amendment process is not "tyrannical".
DiogenesLamp: "So you give us an implicit "yes", to the question, else you would not try to immediately defend the claim that it wasn't being threatened."
You read too much into my words.
The historical fact is the 1860 Republican platform did not threaten slavery in the South.
It was, of course, an abolitionist-friendly document and Lincoln the first openly anti-slavery president ever elected.
But in November 1860 he had not even taken office, and Washington, DC was under control by the slavery-friendly Democrat Buchanan administration.
So no actual threat yet existed.
That's why Deep South Fire Eaters' declarations of secession were "at pleasure".
DiogenesLamp: "Apparently it was, because when Lincoln had the chance, he ended it.
Now you may argue that was because he wanted to put the screws to people with whom he had just fought a war, but can it be doubted that absent a war he would have thrown up every sort of 'executive order' restriction on it that he could have managed?"
Lincoln's Republicans were pledged to prevent the expansion of slavery into western territories which didn't want it, and that you can be certain Lincoln would do.
But absent Civil War, there's no other obvious step Lincoln would take to put restrictions on slavery in the South.
DiogenesLamp: "Would he have interfered with it in all manners possible?
The People of the South thought he would, and when he had the chance, he did in fact do this.
So were their fears of him unfounded? Should they have ignored their own impression of the man and simply trusted him? "
But only Confederate declaration of war on the United States created the constitutional conditions where Lincoln could declare emancipation for slaves as "contraband of war".
That's precisely why Lincoln's Emancipation Proclamation did not include Union states like Maryland, Kentucky or Missouri.
Constitutionally, Lincoln had no authority to free slaves where they were already lawful, only in states at war against the United States.
DiogenesLamp: "So to go back to "x's" point, someone threatening what you regard as essential to your society creates a just cause for revolution."
But since the alleged "threat" was purely imaginary, Deep South Fire Eaters' declarations of secession were strictly, "at pleasure".