I’m not sure your analogy works. Harpers Ferry was lawfully suppressed. Most law abiding citizens of the US were against the Revolutionary violence of John Brown. Similar to the “hands up don’t shoot” madness. The Republicans strongly denied any association with the man and his Revolution. Lincoln campaigned for no slavery in new territories only.
I respectfully disagree with your assessment. Look how many Northerners were supportive of the BLM riots. Pretty much the entire congressional delegations from the Midwest, the mid-Altantic, and the New England states were supportive, and there was no red wave to sweep them from office for their soft-on-crime stance.
Given what happen in Seattle with CHAZ, I would be willing to bet that allowing those rioters to break into an armory, steal military weapons, and rampage through the countryside killing whites at random would not have changed the northerner’s opinions. That is, provided those roving bands did not attack Martha’s Vineyard.
This is what happened at Harper’s Ferry. While Brown and his team were brought to justice by southern courts, the northern sympathy was still there … just as it is today.