And you are not, I'm quite aware of that. And your hyperbole aside, I'm still trying to figure out the whole "violent overthrow of the Constitution" claim. The Wills quote certainly doesn't support that, regardless of what the context of the quote actually is.
If, and I say if, Lincoln was fighting the war to “free the slaves” as the Gettysburg speech implied, he was fighting to overthrow the constitution of the United States.
The U.S. constitution enshrined slavery. Thirteen of the original 13 states had voted to make the U.S. constitution pro-slavery.