Yea, I know - pretty stupid of them, wasn't it?
They did have to protect the states right to govern themselves which the federal government was usurping.
Incorrect.
The slavery question could have been solved with out a war but the north would have had to let their greater goal of gaining control for the central government go and they weren’t going to “let a tragedy go to waste”.
This is a complete misread of the history (I suspect intentionally so). Slavery was on a dead-end street. It had already been outlawed in virtually of the recognized "civilized" countries. It had already been outlawed - or a pathway to emancipation designed in every northern state. There were many attempts put forth to peacefully resolve the issue but any such talk was immediately and forcefully rejected by the slavers. The southern slavers ruled the roost. they held the money, the power, and the influence in the south - and for most of our nations history the country. What they said went. They said "no" to the end of slavery and went to war to underscore that rejection.
So the north was so anti slavery that it’s president when he issued the emancipation proclamation chose only to apply it to the states in the CSA conveniently letting it stand in the northern sympathizing states. By the way Britain and France abolished slavery in their prospective countries only not the territories they controlled untill after the United States. Germany did so after their defeat in WWII. So once again you speak of that you do not know, unlike you I assume you just don’t know, not that it is intentional.