Why, then, should the D of I have not simply been a one-liner announcing that fact? You explain away all the D of I except what suits you with "'should not" is a suggestion, not a requirement." We've already been over that - the D of I is not mandatory legal authority but rather persuasive authority and yet the D of I does state some requirements for secession already mentioned.
Here's one I haven't yet mentioned:
a decent respect to the opinions of mankind requires that they should declare the causes which impel them to separation.
The rest of the D of I, which you summarily reject, explains and shows what a declaration of session should look like, including what are NOT "light and transient causes".
Of course, there's a problem with your rather simplistic free-to-come-free-to-go premise about formal associations. When you as a principal freely join or form a corporation or a partnership with others, mutual trust is formed, mutual benefits are conferred, and you and the others generally have skin in the game. And it is generally contractual. You don't just "back out" of a contract simply because you freely entered into it. Usually you cannot just "leave" a formal association or break a contract just because you decide to without a penalty because others who have relied on your association are now suffering detrimental consequences from your decision. Marriage is probably the easiest example. Associations in the business world like partnerships and corporations are another example.
Usually, a good business association includes agreements on how disassociations will work. Usually you have to have a good reason for leaving and if not, you may have to pay some kind of penalty. The point is your simplistic scenario of freedom to leave without consequences, is not how formal, contractual associations, including political associations, work out in real life.
In this case, the Constitution itself was tailored and ten amendments added to accommodate all potential ratifying states. Those that hated slavery held their nose and allowed it in the Constitution believing that the Union was the most important thing and that slavery would naturally die out, which it would have I think. And there is a legitimate argument that statehood is a contractual agreement with the Union and one that can't simply be broken without certain steps having been taken.
The D of I is persuasive authority about what it takes to legitimately disassociate or secede from a government. Your premise denies the need for a D of I that explains session to the world, only possibly an announcement of secession. I and our Founders would disagree with you. Not sure what else there is to talk about.
No it did not. An organization, voluntarily entered, ought to be voluntarily leavable.
Why, then, should the D of I have not simply been a one-liner announcing that fact?
Because it wouldn't have produced the sort of impact the founders were wanting. King George III mostly ignored it, but the rest of the European countries marked it, and so did the English public.
We've already been over that - the D of I is not mandatory legal authority but rather persuasive authority and yet the D of I does state some requirements for secession already mentioned.
It asserts that it's authority derives from "the laws of nature and of nature's God." There is no higher authority. This was at the pinnacle of the "Natural Law" enlightenment which was sweeping Europe and America at the time. In the 1770s, "natural law" was a thing. It was a body of thought that explained the rights of man in regards to certain fundamental assumptions. That men were created by God, and " endowed by their Creator with certain unalienable Rights".
a decent respect to the opinions of mankind requires that they should declare the causes which impel them to separation.
What is the target object of that sentence? It is "A decent respect to the opinions of mankind."
It isn't setting forth a necessary requirement to leave, it is setting forth a requirement for what must be done if you wish to demonstrate respect for the "opinions of mankind."
Whether "mankind" respects you or not is irrelevant to your having a fundamental right to stop associating with other people, if you so wish.
The rest of the D of I, which you summarily reject, explains and shows what a declaration of session should look like, including what are NOT "light and transient causes".
Should? Who are you to say what a Declaration of Independence should look like? That's just a bunch of formal pomp and circumstance gobbledygook.
I am talking about natural rights, and you are talking about "following symbolic precedent." It's like asserting to someone that they must be your friend until they have given you some sort of formal written document which gives you reasons that you consider satisfactory.
No. You aren't owed an explanation, and your friend's right to leave your company is not contingent upon whatever formalities and flowery language you wish to demand.
A friend or a girlfriend does not have to justify her reasons for leaving you.
And there is a legitimate argument that statehood is a contractual agreement with the Union and one that can't simply be broken without certain steps having been taken.
When you explain to me how this bond should have been regarded as stronger than the English Union, you will have my attention. Bear in mind, your explanation must clarify how we had a right to leave England, but how the Southern States did not have a right to leave Washington D.C.