Let's suppose the world's legitimate scientific institutions and academies, climate scientists, and most of the world's governments are wrong.
Maybe, as some people have argued, they're involved in a massive conspiracy to impose a socialist world order. Maybe the money's just too damn good. It doesn't matter. Let's just imagine they're wrong, and that the polar ice caps aren't melting and the climate isn't changing. Or, if you prefer, that it's happening, but that it's a natural occurrence — nothing to do with seven billion people spewing carbon dioxide and other pollutants into the atmosphere.
Would it still make sense to continue rapidly burning the world's diminishing supply of fossil fuels? Does it mean we shouldn't worry about pollution?
Democracy is utterly dependent upon an electorate that is accurately informed. In promoting climate change denial (and often denying their responsibility for doing so) industry has done more than endanger the environment. It has undermined democracy.
There is a vast difference between putting forth a point of view, honestly held, and intentionally sowing the seeds of confusion. Free speech does not include the right to deceive. Deception is not a point of view. And the right to disagree does not include a right to intentionally subvert the public awareness.