I fully agree but AFAIK the Civil War was about states' rights. (Edit: To be clear, it was the right of states to not enforce slavery.) Correct me if I'm wrong but the sequence of events was something like this:
Several slavery-averse states passed laws that would automatically free any slave who entered them. The states who were reliant on slave labor argued that states should not have the right to pass such laws. Their complaint failed and the laws were upheld. The slave states decided that they didn't want to be part of a country that didn't protect their ownership of people and seceded.
So states' rights would've been the underlying reason, just not in the way Confederate apologists think it was.