Nothing in those laws, I repeat NOTHING, prevented southerners from going into shipping, insurance, the packet trade or any other venture they wanted. What convinced them not to invest in those things was the large profits that could be made in the cotton industry with far less risk.
It was the choice of Southern people with money to invest that money in land and slaves rather than ships or factories.
You clearly haven't studied this issue. The Federal government provided subsidies to Northern Shipping companies, who also had what would be considered monopolies in modern times. You do know how monopolies work, don't you?
The South used to have several shipyards that built ships, but over time they all closed down because they could not compete with the Northern shipyards, which the government favored. Government subsidies gives any company that receives them a financial advantage over those who don't.
What convinced them not to invest in those things was the large profits that could be made in the cotton industry with far less risk.
You need to read more about what happened. After South Carolina seceded, Charleston became a boom town with every hotel booked, every dock hired, and a massive inward flood of money and people from the North began.
There were projects to build more warehouses, hotels, homes, docks, and everything else. I read a newspaper account of it from the Charleston Mercury, and people were amazed and flabbergasted at all the capital investment pouring into the city.
And of course New York didn't like it.