The facts I have studied came out of South Carolina's own list of reasons why they wanted to become a sovereign nation, if they had all these grievances you talk about why didn't they list them, instead of slavery being their one main grievance? Do you think they had a secret agenda? and if so, why would you think that, when clearly they were very upset with the new president coming in that wanted to abolish slavery. Several statements in their list of causes make it very clear that they thought their economy was in danger if slavery was abolished.
This is what SC had to say about this Article of the Constitution,
"No person held to service or labor in one State, under the laws thereof, escaping into another, shall, in consequence of any law or regulation therein, be discharged from such service or labor, but shall be delivered up, on claim of the party to whom such service or labor may be due."
In many of these States the fugitive is discharged from service or labor claimed, and in none of them has the State Government complied with the stipulation made in the Constitution. The State of New Jersey, at an early day, passed a law in conformity with her constitutional obligation; but the current of anti-slavery feeling has led her more recently to enact laws which render inoperative the remedies provided by her own law and by the laws of Congress. In the State of New York even the right of transit for a slave has been denied by her tribunals; and the States of Ohio and Iowa have refused to surrender to justice fugitives charged with murder, and with inciting servile insurrection in the State of Virginia. Thus the constituted compact has been deliberately broken and disregarded by the non-slave holding States, and the consequence follows that South Carolina is released from her obligation.
And these lines here tell you how South Carolina felt about their present status of holding slave was being "protected".
On the 4Th day of March next, this party will take possession of the Government. It has announced that the South shall be excluded from the common territory, that the judicial tribunals shall be made sectional, and that a war must be waged against slavery until it shall cease throughout the United States.
The guaranties of the Constitution will then no longer exist; the equal rights of the States will be lost. The slave holding States will no longer have the power of self-government, or self-protection, and the Federal Government will have become their enemy.
It would be nice if the WBS was started for a more noble purpose, but unfortunately, it was just over greedy landowners wanted to keep things status quo, that is not to say though that most of the Southern men who fought in the war were not fighting for a noble cause, to keep their land from being invaded by the North once war was inevitable.