Terrorists who attacked the United States? Whose revising history now? The split between the North and the South was over far more than just slavery which didn't become an issue until TWO YEARS into the conflict. Obviously you've watched way too many showings of Mandingo to have an intelligent thought regarding the War of Northern Aggression.
Slavery was the issue. South Carolina started it. Anything else is historic revisionism.
There was one reason the Slavers attacked the US and that was to preserve their Empire of the Whip and the Lash. There was NO other reason for their attack.
Any other claim is sheer ridiculousness. Lincoln did not fight the war to free the slaves but simply to preserve the Union. Freeing the slaves became a tactical and strategic policy to further the war aims. They were freeing themselves in any case whenever the Union armies appeared. Slaves were overjoyed with the prospect of Freedom like all Americans except those fighting to preserve their bondage.
American installations were attacked by the Slavers whose entire existence was based upon Terror. There was no other means of keeping the Blacks enslaved except through terroristic means: murder, beatings, ripping families apart. Thus they were clearly terrorists.
You probably thought they just loved "Ole Massa" so much they couldn't even think of leaving since your historical understanding is approximately at the level of Gone With the Wind.
For the Union perhaps. For the confederacy defense of slavery was by far the single most important reason for the rebellion from the very beginning.