Well, and Hitler was a vegetarian. What's your point?
Btw, do we have any sources / evidence for whether the confederacy only believed that specific point for the specific question of whether the states or the union should decide about slavery?
Or did they also have differences in opinion from the northerners on eg the role of municipalities and counties in educational policy or monetary questions etc?
The point is we generally agree that some human rights are too important to leave to local jurisdiction. They are universal, and everyone has an interest is seeing them upheld.