“the association makes little sense for confederates to use it”
Well, they did. That’s a fact.
Perhaps you’re thinking of those passages in the Bible where slaves are encouraged to rise up and slay their owners.
“Well, they did. That’s a fact.”
Because you say so?
“Soon, though, a new version appeared that hitched the old tune to a more militant cause. When the abolitionist John Brown was executed in 1859, someone created a new, fiercer set of lyrics; the song now declared that “John Brown’s body lies a-mouldering in the grave. His soul is marching on!”
By the time the Civil War began in 1861, the John Brown version of the song had spread throughout the Union army. Soldiers added new verses as they marched through the South, including one that promised to hang Jefferson Davis, the president of the Confederacy, from a tree. Meanwhile, Confederate soldiers answered back with their own version, in which John Brown was hanging from a tree.”
http://www.loc.gov/teachers/lyrical/songs/john_brown.html
Just as I stated. The only way secesh would sing a version would have been in response to Union forces.