I am amused by the poster at your link. It doesn’t say “We are peacefully leaving the Union” It proudly and provocatively proclaims “The Union Is Dissolved!”
So much for “we just want to go our own way”
Right, and some posters here even claim the Union itself was dissolved when South Carolina & others declared secession.
They say that's what makes Lincoln's "aggression" against Confederates soooooo unconstitutional.
Of course, it also made Northerners who disagreed that SC could dissolve the Union on its own hopping mad and willing to fight against Confederates.