Denialism is abdication of responsibility. First towards others, but ultimately towards self.
When problems mount in every direction, society has a choice to face those problems or to ignore them. The easiest path to take is to rationalize them away. Pretend they don't exist. Create an entirely new genre of fake-believe that spends its entire time discussing topics that are totally irrelevant to the major problems at hand. All to extrapolate the impossible and give the sheeple a false sense of confidence.
Path of least resistance.