“the right of transit”
So you don’t notice that it also mentions “the institution of negro slavery”
You didn't notice Dred Scott allowed slave owners to transit with their SLAVES as well?
Also, have you failed to notice despite the fact that I've posted it twice already that this prohibition applied to the Central Confederate government only and not to the states in the Confederacy? In other words, the Confederate government could not force a state to abolish slavery. A Confederate state however could decide to do so on their own and there was nothing the Confederate government could do about it. They were even willing to admit states that had already banned slavery.