So then certainly for the South the war was about slavery.
This was the vision of the Leadership of the Confederacy. I cannot say this played into the vision of your typical southerner who was eking out a livelihood unrelated to the peculiar institution. They, for the most part were dragged in to protect their life and property from an "invader".
It is with too broad of a brush to say "for the South the War was about slavery". It is no exaggeration to say that for the Leadership of the Confederacy the War was most certainly all about slavery.