For that matter, Abraham Lincoln's candidacy was promoted by Harpers Ferry, Seward of New York being the favorite for the Republican nomination prior to that event. The Republicans had no desire to be directly associated with John Brown, and Lincoln appeared to be more moderate than Seward on the slavery issue. You may recall Seward's speech on the "irrepressible conflict" between the North and the South. He was a radical before the war, and a radical during Reconstruction as well.
Some slaveholders in the South may have been agreeable to abolishing slavery if fairly compensated for their slaves. As best I know, that proposal was never seriously advocated by anyone on the abolitionist side. As you probably know, that's how slavery ended in the British Empire.
Issues involved in secession and the Civil War are more complex than simply saying, "It's all about slavery", or "No, it was about states rights." People who argue on that level sound like angry children yelling at each other. It's not persuasive and doesn't illuminate or educate.
Don't mean to beat a dead horse, but it would be nice to hear from someone who can outline the great debate over states rights that split the Democrats in 1860.