The free state was a weird place. Basically exactly what Ancaps want the world to be like. There were a few colonies of freed slaves, but way more ruthless capitalists and bloodthirsty racist militias. John Brown's group was constantly being attacked and people in his community were being kidnapped and killed (his son was kidnapped, tarred and feathered by a racist militia).

Harpers Ferry was retaliation that barely even compared to the constant harassment and violence suffered by John Brown and the free slaves, but of course, after reconstruction was scuttled we have to take the revisionist line that he like murdered poor innocent racists in their sleep instead of fighting against a group that made their living murdering innocents.