Lack of understanding. Coal is actually a complete spectrum of material with multiple facets (energy content, moisture, ash, etc). Then you need to take into account location and logistics... way too hard for a TV sound bite.
Simpletons like things simple... lumping them into one bucket (or sound bite) makes them easier to digest. The Green groups have seen how the general public easily comprehend the metal markets (which are simple; after all a pound of copper is the same whether it came from Escondida or Olympic Dam) and since coal does not fit into one basket they have tried to keep it simple in two baskets.
