Using social construction to promote irrational viewpoints in politics goes back to Gasset's 1932 book "Revolt of the Masses". What is novel and Postmodern is the new technology of social media where group/mass viewpoints can overwhelm science, law, rationality, and social norms. The Postmodern agenda is to create a socially constructed 'hyperreality' that overlays and dominates the real world. In Postmodernism it doesn't matter what is 'true' it matters what is most 'authentic'.