Yes as I said, only 4 issued declarations of causes. 3 of the 4 mentioned things other than slavery. (I notice this does not include the address of Robert Barnwell Rhett for South Carolina...which is very disingenuous as it was sent out along with the Address).
Here is the Corwin Amendment.
https://en.wikipedia.org/wiki/Corwin_Amendment
Readers can decide for themselves why the 7 original seceding states turned down slavery effectively forever by express constitutional amendment if protection of slavery had really been their main concern.
And of course they mentioned reasons other than slavery, like Constitutional rights and state's rights. The problem is, they saw owning slaves as among those rights.