No worries. We all make mistakes on occasion. If you are going to argue on the internet, you need to have a thick skin. :)
How was the federal government destructive of those ends?
I believe that is entirely a matter of their perception. You know the usual spiel. The Gradual elimination of slavery, and therefore the eventual burden on their "business" model, Unfair tariff policy, and fear of a President using "Executive Orders" in the manner of the current President, and so on.
I would suggest it is the people who thinks their ox is being gored that should decide if they regard their existing government as "destructive of those ends." A lot of the Colonists didn't think England was treating them so badly. It was the "troublemakers" that did. They persuaded sufficient numbers to decide on a break.
Much like the British acceptance of American independence.
I dare say Britain had far more of a choice than did the Southern States. Britain could still fight and kick our @$$, they just decided it wasn't worth the trouble. The Southern states were in no such position while having that Union foot on their necks.
Quoting Abraham Lincoln
I hold that in contemplation of universal law and of the Constitution the Union of these States is perpetual. Perpetuity is implied, if not expressed, in the fundamental law of all national governments. ...
...Again: If the United States be not a government proper, but an association of States in the nature of contract merely, can it, as a contract, be peaceably unmade by less than all the parties who made it? One party to a contract may violate it—break it, so to speak—but does it not require all to lawfully rescind it? ...
...I therefore consider that in view of the Constitution and the laws the Union is unbroken, and to the extent of my ability, I shall take care, as the Constitution itself expressly enjoins upon me, that the laws of the Union be faithfully executed in all the States.
One thing you can say for certain, Lincoln sure could argue like a lawyer. There is but one glaring discrepancy in his argument. If what he says be true, then by the same argument we should still be part of England. Their Union was perpetual too, you know. United Kingdom. Union Jack.
Their Flag even represents their union by merging the flags of the three primary "states" of the United Kingdom. (England, Scotland, and Ireland. I guess Wales goes a begging.)
Allegiance to England was Perpetual until we invoked an understanding of natural law (Provided by Vattel from the Swiss Republic) that demonstrated it was not.