You are both taking it out of context, and wrong about it being a "necessity." They called it a necessity, but the British people (corresponding to the Northern people in 1861) did not agree with them that their gripes were actual "necessities." They regarded them as "at pleasure" opinions.
Regarding your taking it out of context, they claimed their gripes made it necessary to leave, but their central premise was that people had a right to leave just from dissatisfaction, and "necessity" wasn't required, though they did caution against leaving " for light and transient causes, but this was a suggestion, not a requirement.
I have been re-reading the notes on the constitutional convention and the federalists and anti-federalist papers. I would not characterize the federalists arguments as fluff but they certainly downplayed the fears of the anti-federalists.
I completely agree with you that the anti-federalist were right about a lot of things and am glad their push for amendments was successful, but also glad they failed in stopping the ratification of the constitution. One of the leading Anti-federalist, Patrick Henry, gave a speech at the Virginia ratification convention arguing against adoption of the constitution. In it he states the constitution will do exactly what you and the rest of the lost cause brigade claim it didn’t do. Take away the states sovereignty.
“I rose yesterday to ask a question which arose in my own mind. When I asked that question, I thought the meaning of my interrogation was obvious. The fate of this question and of America may depend on this. Have they said, We, the states? Have they made a proposal of a compact between states? If they had, this would be a confederation. It is otherwise most clearly a consolidated government. The question turns, sir, on that poor little thing — the expression, We, the people, instead of the states, of America. I need not take much pains to show that the principles of this system are extremely pernicious, impolitic, and dangerous. Is this a monarchy, like England — a compact between prince and people, with checks on the former to secure the liberty of the latter? Is this a confederacy, like Holland — an association of a number of independent states, each of which retains its individual sovereignty? It is not a democracy, wherein the people retain all their rights securely. Had these principles been adhered to, we should not have been brought to this alarming transition, from a confederacy to a consolidated government. We have no detail of these great consideration, which, in my opinion, ought to have abounded before we should recur to a government of this kind. Here is a resolution as radical as that which separated us from Great Britain. It is radical in this transition; our rights and privileges are endangered, and the sovereignty of the states will be relinquished: and cannot we plainly see that this is actually the case?The rights of conscience, trial by jury, liberty of the press, all your immunities and franchises, all pretensions to human rights and privileges, are rendered insecure, if not lost, by this change, so loudly talked of by some, and inconsiderately by others. Is this tame relinquishment of rights worthy of freemen? Is it worthy of that manly fortitude that ought to characterize republicans? It is said eight states have adopted this plan. I declare that if twelve states and a half had adopted it, I would, with manly firmness, and in spite of an erring world, reject it. You are not to inquire how your trade may be increased, nor how you are to become a great and powerful people, but how your liberties can be secured; for liberty ought to be the direct end of your government.