Why did slavery become the issue that caused a war if the US had been a slave holding republic from the founding? What possible real problem for someone in Michigan would be slave holding in Mississippi, you note I write real problem. Not one generated by an overactive psyche and a lot of slavery screaming preachers.
But beyond that, who's to say that slavery wasn't a real issue? Who's to say that concentration camps or Chinese prison labor or religious persecution or torture or abortion aren't real issues?