Are you saying absolutely that states rights was exclusively the province of the slave owning south or that the slave owning south used it for exclusively for slavery?
Either position is wrong to varying degrees, IMO, but the 2nd less so, because slavery was the cause celeb for so many of the chief secessionists in the South, as demonstrated by their writings. The reason that the statement that the south's sole use of states' rights was about slavery ignores serious disagreements between the Southern state governments and Jeff Davis' central government that had nothing to do with slavery and everything to do with where the authority of the central government stopped and the state governments started. Below is in interesting and even handed review issues of states rights in the Confederacy. You can look at the comments and find that one or two even took your position.
https://cwcrossroads.wordpress.com/2011/03/26/the-confederacy-and-state-rights/
Dude, just say "slavery".