So it means that they are all the same in this area of their performance. Diesels all provide a great deal of power. What counts is the performance and reliability and durability of the engine, its various systems (electrical, cooling, emissions controls, suspension, AC, etc.), the strength of the frame, rust proofing, quality control overall.
Even for towing the testing that has covered aspects such as the coordination of the engine, exhaust brake, and transmission operation are more relevant to actually using a truck for towing a heavy load. This is an area where there have been big differences in performance in past years between the 3 companies' 1-ton pickup trucks.
I would hope that anyone buying a vehicle for serious towing would not be seduced by marketing hype though others like the OP are going to get sucked in.