The Republican Party platform of 1860 was revolutionary in denying the Supreme Court’s authority, not just disagreeing with the decision. Secession was counterrevolution.
A responsible party could have challenged the Dred Scott decision in many political ways, but the party of Lincoln chose confrontation. Just as today’s left wants it all in one bite, disaster followed when they got what they wanted.
What’s the definition of a communist: a liberal in a hurry.
Or, rather, no grievances that would be appealing to modern apologists attempting to shoehorn in a modern political scene into the era. Many of the things that popped up concerned the internal affairs of other states (Southern states took a dim view of Northern states allowing abolitionist papers to be published freely, or their ignoring the Federal fugitive slave laws, or not recognizing slave ownership within their own territory), and that shouldn't have been their business under the doctrine they were supposedly advocating. The declarations of secession of many Southern states explicitly name this fact (Northern state's disobeying Federal pro-slavery legislation) as a major point for leaving the Union.