You're right that CAFE is literally designed to favor trucks. And the definition is so vague that even vehicles like the PT Cruiser are considered Light Trucks for the purposes of CAFE. It is also designed to hurt small cars, because vehicles with footprints (wheelbase * wheel wide) smaller than a Mustang (literally, to the square inch) have to face ever-more-strict CAFE standards.
As a result, cars like the Fit are might face a CAFE penalty while a base F150 does a-okay despite getting like half the fuel economy. And that's not even getting into BS like flex fuel credits (basically, being flex fuel capable is like adding ~5mpg to the vehicle CAFE score).
This is exactly why every small vehicle is a crossover anymore (they are light trucks for CAFE purposes), and why cars like the Civic get are today, the size an Accord was in 2005 (CAFE is less strict the larger the vehicle is).
Which seems pretty crazy if the net effect is that any car manufacturer has to produce a full line if they want to build any inefficient cars.
My dad had a Ranger in 97 that was just about the perfect truck for day-to-day use. It fit 2 adults comfortably, had a tiny 4 cylinder engine, got great gas milage, and could be used to pull a small trailer. He was crushed when Ford got rid of the Ranger. And what they've released now is basically the size of the old F-150 from the 90s