"Its ironic that Jews had such a good relationship with anti-bellum southerners and after the war they became the objects of attack by the KKK along with blacks and Catholics."
Makes one wonder, but then it took the South over a century to recover, so scapegoating was a much easier task. Without romanticizing the South, had there been no slavery, it seems that the North's cause may have been interpreted a bit differently by historians. I guess the question is whether they would have even gotten approval for the war based on economic reasons had there been no slavery.
No slavery - no civil war.
Not every Southerner supported Slavery and not every northerner supported it, but the few radicals of the north and south who brought on the war did so over the issue of slavery.
Had there been no slavery there would have been no war, so in that sense you are correct.
It was only the South which fought about Slavery not the North. Preservation of the Union was the North's goal.