There's some real science there for a couple of reasons. Protein is a macronutrient you can be malnourished if you don't get enough of even if you eat enough calories and the right micronutrients, and if most of your calories are from protein then you're actually probably not getting as many "burnable" calories as you think you are because (1) the amount of protein you need to meet your daily protein needs never enters the citric acid cycle to oxidized for ATP regeneration, (2) protein is the macronutrient that feels the most filling, and (3) excess protein that goes to the liver to be converted into carbs loses around 30% of its net usable calories due to the energy required for that conversion.

The way we count calories is based on how many calories are in a meal vs the resulting scat, and that just isn't an accurate representation of how the body processes protein such that a protein-heavy diet doesn't have as many calories as you probably think it does, which makes it a healthy choice in an environment where most food-related health problems stem from overeating.

However I agree with your skepticism insofar as when they say "prioritizing protein" they probably mean "prioritizing meat," which is more suspect from a health standpoint and looks somewhat suspicious considering the lobbyists involved.