Those crash tests don't really give the full picture of body-on-frame collisions with other vehicles.
In barrier collisions, the force of impact is almost entirely absorbed by the vehicle being crashed. It simulates two identical vehicles hitting each other head on.
In a real collision, since the frames are very rigid, they end up causing the other car in the collision to absorb a lot of the force that could have been dissipated by a proper crumple zone. As long as the vehicles are relatively close in mass, a unibody car hitting a body-on-frame car will end up having to dissipate a disproportionate amount of the impact energy.
Of course there's a lot more to it than that when considering occupant injuries.