What would be the motivator for this kind of clause? I can't imagine radio-device manufacturers would appreciate the additional expense, and at least some of them must benefit from consumers buying those products specifically for customization. Are the national governments pushing for more radio control? Is there some kind of crisis of radio abuse? Or is it an indirect way to give governments more punishment tools, b…
Looking at this rule from another angle, I think the objective is to have a single entity to blame if interfering device is found. In this context this may seem rational -- all the firmware released that is mangling with intentional radiators needs to be tested to prove it is compliant. However, the method creates extra complexity for the device manufacturers and as time has shown -- does not really improve the matters in the long term, you will just get a fleet of devices running old firmware with unfixed bugs. Manufacturers often do not like it either, specially in the management.
I think it may be a classical example of "The road to hell is paved with good intentions" or Hanlon's razor*