More indissoluble than the United Kingdom which existed for over a 1,000 years? How can it be more indissoluble than that?
On what basis do you assert that the much older Union could be broken, but this relatively young one with a founding document that explicitly states it is the right of all people to have independence, cannot?
Comparing apples and oranges doesn’t help your argument. There was no consent of the governed when the colonies were under the King’s rule. That is the reason for the Revolution in the first place.
That changed with the constitution which set up procedures to change things if they aren’t working right. There was no right to secede in it.
There are no lame excuses which would allow and insurrection to be legal. The power to suppress them is EXPLICITLY authorized by the constitution.