Correction. My last paragraph should have read...
Dred Scott represents the North making an unconstitutional decision in favor of the South. The South could hardly complain about that. The Missouri Compromise had been repealed and later declared unconstitutional (kinda like sentencing someone to be hung until dead and then sentencing him to be shot). The Kansas Nebraska Act favored the South as well. so it appears the South was short on constitutional grievances against the North which were necessary IMO to justify secession. (There were 27 specific legal grievances listed in the Declaration of Independence from England’s rule.)
If you read the text of the Declaration of Independence, it makes it clear that the listing of grievances is a courtesy, not a requirement.
...a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.
The Declaration of Independence states that people have a God given right to leave for whatever reasons they so choose.
That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, — That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness.
Northerners have been taking note of that since the Compromise of 1850 and Fugitive Slave Act.