Gotta partially disagree with you on this one. New York was the primary point of entry because it was about the closest to Europe. A given ship could make more trips in a year, and more money for the owner, than by making the much longer trips to New Orleans.
NYC also had probably the best rail routes to the interior of any eastern port. It was the port most immigrants wanted to go to.
The point, however, really ought to be that Williams’ claim is flat untrue, and the implication he tries to draw from that untrue claim is also inaccurate.
There is simply no reason to believe imports were consumed more heavily by southerners than by the nation as a whole. Thus they did not pay more in tariffs than anybody else.
They did have a legitimate beef about protective tariffs. But those were not sectional in their effects, they were occupational.
Workers and owners in the protected industries got the benefits. Everybody else, north and south, paid the costs.
A farmer in OH paid exactly the same tariff on imported machinery as a planter in MS.
Then why did exports flow from southern ports to Europe instead of being sent from there to New York and from New York overseas?