Read further: "To prove this, let facts be submitted to a candid world."
Jefferson and the Continental Congress recognized that they had to make a case, to prove that they were indeed oppressed and that there was no available avenue of redress for their grievances.
They weren't saying "FU We do what we like" to Britain or to the rest of the world.
You can read even further:
In every stage of these oppressions we have petitioned for redress in the most humble terms: our repeated petitions have been answered only by repeated injury. A prince, whose character is thus marked by every act which may define a tyrant, is unfit to be the ruler of a free people.
Nor have we been wanting in attention to our British brethren. We have warned them from time to time of attempts by their legislature to extend an unwarrantable jurisdiction over us. We have reminded them of the circumstances of our emigration and settlement here. We have appealed to their native justice and magnanimity, and we have conjured them by the ties of our common kindred to disavow these usurpations, which, would inevitably interrupt our connections and correspondence. We must, therefore, acquiesce in the necessity, which denounces our separation, and hold them, as we hold the rest of mankind, enemies in war, in peace friends.
The Founders recognized that it was necessary to work within established legal processes, but in their day the necessary processes either didn't exist or had broken down. Fighting had already begun. It was different in 1861. Constitutional and democratic processes for the redress of grievances existed but were ignored by the secessionists.
You should read this book.
Thomas Prentice Kettell's book was refuted by Stephen Colwell's The Five Cotton States and New York, a pamphlet of 1861. You can find the text on line or look up my many posts here about the two books.
Early on it says that slavery is necessary because otherwise these people will sit on their @$$e$ and do nothing all day long. It presumes to dictate what is best for people who would prefer to sit on their asses rather than accomplish anything. I.E. Forced Work.
Like people didn't work hard after slavery was abolished? You are off your meds again and revealing things that hurt your case and your reputation.
Why do you put so much stock in their listed grievances? As I pointed out, the Canadians did not find these conditions so intolerable, so the degree of misery involved depends upon the perspective of those who suffer it.
It is irrelevant to their claim that under "the laws of nature and of nature's God..." "...Governments are instituted among Men, deriving their just powers from the consent of the governed,". This principle stands on it's own merits and does not require grievances to make it valid.
The founders listed grievances in an effort to win support for their cause, not because it was necessary to the assertion of the principle of "consent of the governed."
It was different in 1861. Constitutional and democratic processes for the redress of grievances existed but were ignored by the secessionists.
The existence of a "process" does not mean the grievances will get addressed. This is the fallacy of the Democratic process, that two wolves and a sheep can vote on what's for dinner. It makes no difference if there is a "process" when it does not produce a result that is tolerable for all parties.
The North had the government sewn up, and there was nothing the South could do to fix any of this. Under the existing system, they not only had to keep paying for 3/4ths of all federal revenues, they also had to keep losing about 40% of their export revenues to New York.
They were stuck in a position where their only option within the system was to keep feeding the beast to the North, all the while listening to the chorus of smug Northern Liberals telling them what horrible rotten people they were.
Sort of like Modern America.