To join the Confederacy the state had to enshrine slavery in it’s constitution. It was actually giving up the right to choose.

It was slavery or union.

The South went out of it’s way to make the war about slavery.

Best short explanation I heard, was in college. The cause of the civil war was slavery, the civil war was not fought over slavery.

This helps understand why the south started fighting to keep slavery but the union did not start fighting to end slavery. Some halfway through the war abolition started getting steam but racism and bias continued through and after the war.

Edit: "Sates right’s (To allow slavery) is a common misdirect, the same as calling it the war of northern aggression, to not flat out say slavery. But hey they get to say the quiet part out loud now so maybe they wont try and be coy.