Money. They wanted to keep the money earned by their exports to Europe instead of losing 40% of it to New York.
They also wanted to set up Shipping industries, Factories and other industries rivaling with and competing against Northern manufacturing interests.
Charleston was going to become "Carthage" to New York's "Rome", and "Rome" wasn't going to have any of that.
"Rome" sicced their Washington Agents on the South in order to stop the money loss, and then 18 months after the fact, their agents declared that ending slavery had become a goal of the war.
In all fairness, they had to come up with something to rationalize why they had killed so many people, and the last thing they would tell them was the truth; that the war was started to keep the money flowing into the pockets of the Wealthy Power Barons of New England.
No, they certainly couldn't tell the people that!
But that is what the financial records from the time shows.
Your historical facts are totally wrong, but it’s not worth my time to go thru all the true facts with you. If you want to side with the UN, you go right ahead and do so.