The first point doesn’t hold though. it is always better to have a ship run with cargo than without, in terms of efficiency. Afterall the point of the ship moving is to transport cargo.

For the cooling i am also sceptical. It was common all over Europe to trade with ice cut out of glaciers and frozen lakes until the invention of the cooling pump made electrical fridges a thing. If you store the ice in somewhat well insulated containers, it will cool itself quite decently for long travels. Icecellars were common to hold Ice that was collected in winter and lasted for cooling all throughout the year even in the mediteranian areas.

I also find this business obscene, but i do not see, that it would be more harmful, than sending empty ships around the world.