Charleston had a ship building industry. The "Horizon", which was the first American Ship every seized by the French under the Berlin decree, was built in Charleston South Carolina. James McClure and his Father had ran a shipping business from that Port for years in the 1800s.
It must be easy to make an argument when you simply wave away things you don't like, whether it be a southern politician and secessionist leader's statements, or the southern Declarations of Causes. .
I can find statements that said it was about trade and economic interest. I can cite Virginia's secession statement in which they said they were leaving because of Federal aggression against their sister states.
Sure, if you look around, you can find statements by all sorts of people to support whatever it is you want to support.
I don't put so much stock in what people say as in what they do. People lie. They tell you what they want you to hear.
Lincoln said his violence enabled fleet was a "supply" mission. He said people peacefully voting to leave the control of Washington DC's rigged system was "Rebellion."
When you realize everyone is lying to you, you get to a point where you believe that the only way to know what is actually true is to look at the money.
Follow the money and the power and you will always understand what is happening. Listen to what people tell you is happening, and you will be misled.
Just to be clear, which statements by historical figures will you allow and which will you not allow?
Statements against interest by persons launching an invasion into other people's lands could generally be taken to be true. When Lincoln said he had no objections to the Pro-Slavery Corwin amendment, I believe him.
Status quo of the slaves working down in the South to keep the money flowing into New York and Washington DC, seems like a very good outcome for him and his New York backers.
Then I assume that by that definition, in your mind nothing any southern leader said about the subject can be accepted.
How convenient for you.