The video is talking about the load capability of truck. This has been discussed in other threads here related to towing travel trailers. Once you add your tongue weight, you don't have much left for luggage and people.
A 1400# carry weight, reduced by 800# trailer tongue weight leaves you with 600#. Add two adults that equal 350#, a 50# dog, and 200# of luggage and gear, and you have no more capacity. But, you added bigger wheels and tires that equal 120# more than the factory set, an aftermarket front bumper and winch for maybe 50-75#, a tonneau cover for 30#, side steps for maybe 20#, crap in your Ram Bins, etc, and your overloaded!!!