That is nothing but Brit anti-American propaganda. (The Brits used to be the best at that.)
The Founders did not call themselves "secessionists". They never for a moment pretended that what they did was legal under British law.
They proudly called themselves Revolutionaries, and they were fully prepared to pay the legal price of Revolution.
They played no legalistic games to obscure their treason from the Crown.
Interesting perspective.
“The Founders did not call themselves “secessionists”. They never for a moment pretended that what they did was legal under British law.”
Nevertheless, they did proceed to secede.
“They played no legalistic games to obscure their treason from the Crown.”
If Davis was a traitor, why was he never charged? Certainly that would provide the capstone for the victory for the Grand Army of the Republic and revenge for Lincoln, wouldn’t it?