Why do those on the political Right confuse any regard for truth & honesty in media with a "left-wing" bias?

You might have heard the saying "reality has a Left-wing bias" used to describe the noisy, corporate backed, right-wing minority's perspective on realistic mass media depictions of the world and events that don't fit their narrow, unscientific ideologies. How is it that the Right can so easily ignore reality and continue to push their tired, failed, base, values and world views? Are these people really throwbacks intent on either repeating history or ending it, or can they be informed despite their blinkered politics? Are those on the Right simply less intelligent then the rest of us? Or is it a failure of education that people think capitalism's the latest and best thing? Can people really be ignorant of Marxism and socialism being irrefutably the most influential waves of ideological advance made since industrialisation? Perhaps post-modernist notions of there being no objective truth has devalued empiricism and science amongst the general populous of the West, and helped stripped people of the intellectual tools of critical analysis and deconstruction necessary to avoid unwittingly being taken in by propaganda?