Who encouraged terrorist attacks against Americans for decades
The terrorists in the "Bleeding Kansas" saga were the so-called "border ruffians" who sought to suppress the democratic process using violence. The Kansas-Nebraska Act left it up to the respective residents of the territories to decide whether they wanted to be a slave state or not, and when pro-slavery radicals realized the majority of Kansans wanted to be a free state, they started murdering people, the first murder happening when pro-slaver Frank Coleman murdered free-stater Charles W Dow. A few months later, pro-slavery Missourians would terrorize Lawrence. This was followed by Preston Brooks attempting to murder Charles Sumner on the Senate floor for denouncing slavery and the terror in Kansas.
John Brown's murder at Pottawatomie Creek only occurred
after multiple acts of terrorism on the part of the pro-slavery crowd. Wrong, yes, but it has to be understood in the context of repeated terror attacks by the pro-slavery faction.
This was followed by Franklin Pierce using the Army to cover up voting fraud in Kansas and disperse the government on threat of death.
Pro-slavery out-of-state radicals would then invade Kansas to terrorize the town of Osawatomie, where they were met by none other John Brown, who failed to stop the slavers from looting and burning the place.
I won't recount the whole history of it, but your bald-faced lie about the free staters terrorizing the slavers isn't something I'm just going to let go by.
The vote for Kansas to be a free state was 10,421 to 5,530.
The Confederacy started the war by firing on Ft Sumter.
I think the strongest argument for the Confederacy being in the wrong is how much neo-confederates have to blatantly lie about what's in the historical record.