>>728044Unironically, evolution.
It used to be somewhat reasonable to be religious as an intelligent knowledgeable person, because there was a lot about the world we did not understand. There was a huge "gap" for God to exist in. Science could be seen as an extension of God's creation.
When evolution was discovered, rigorously tested, and finally established as a foundation of biology, the world could finally be explained as a series of natural/physical phenomena. Life was not the result of a divine inventor, but rather a complex systemic process that happened over billions of years. God and the supernatural became wholly unnecessary.
So then we saw a shift in the scientific community and intelligentsia from religion to atheism. Thus the ones who remained religious began to reject science, academia, and knowledge itself. Capitalists further exploited this and transformed Christians into a voting bloc that could be manipulated into supporting the interests of capital.