Consider evolution: The view that man is simply the result of chance evolutionary events gives government moral permission to attempt to mold and shape its' citizens to some desired outcome of those in authority. Other views of man, such as the classical position that he is a created being in the image of God with certain Creator-granted rights, set limits on the amount of meddling the state can do to the human psyche. Those in power might find this view inconvenient to their goals, thus it is not surprising that the bias of public school textbooks is to discuss the evidence favoring macro-evolution, but not that opposing it.
In the same way that evolution can give those in power a justification to concoct grand designs to shape their neighbor's form and mind, global warming can give them a justification for grand designs for their neighbor's property, industry, and habits. So it is once again not surprising that a balanced view of the evidence must come from outside the central authorities.
