Praise of Nat Turner led to the War
Turner was a slave and self-proclaimed prophet who, despite having a kind master, murdered the family that owned him, killing even the wife and kids in grisly ways...then led a rampage doing the same to other families
Puritan Abolitionists like William Lloyd Garrison responded not with sympathy for murdered women and children, but with praise for the murderers!
As Fleming notes in his A Disease in the Public Mind, "Did Garrison express even a hint of sympathy or pity for these stunned, grieving families and their terrified neighbors? Did he confess that his immediate emancipation slogan was wrong, or at least in need of amendment? The only emotion Garrison permitted himself was thinly disguised gloating— and a call for sympathy for the slaves."
Further, Virginians saw the worst of the Haitian Revolution in what had happened. As Fleming notes, "It was as if a chapter out of Santo Domingo's final slaughter under General Dessalines had somehow been reincarnated in Southampton County, a thinly populated rural region not far from Virginia's seacoast. Blacks outnumbered whites by more than a thousand, but most whites owned only two or three slaves and many owned none. Seizing horses from nearby farms, Nat Turner and his swelling band, soon numbering more than fifty men, rode from farmhouse to farmhouse, killing everyone with white skin."
So, what they saw were insane abolitionists in Massachusetts cheering on the grisly deaths of women and children for ideological reasons, which hardened attitudes in an immense way, and led to the cycle of spite, hate, and violence that ultimately resulted in the Civil War
Notably, modern leftists now praise Nat Turner because they too hate white people and want to inflict upon all of us a Haitian-style campaign of murderous genocide in the name of equality
Nat Turner and the Haitian revolt were acts of racial terrorism. You just agree with the target so you don’t see why anyone would condemn them.