Why evangelicals support authoritarians

Evangelicals believe that people can't be trusted to make good decisions. They take an approach that people can't fundamentally trust their own thoughts and they need protecting from an unsafe world that is always tempting them. 

Using this dogmatic prism you can then understand why authoritarianism appeals to them because it introduces a protector who guides them and keeps them safe. Never mind that he is flawed as long as they believe he has been prophetically provided. 

Simplistic thinking like this doesn't require the development of critical thinking skills but instead the adherence to the leader who tells them what to do and provides safety and order for the flock. 

The liberal intellectual stance thinks the opposite and appeals to the fundamental goodness in people to do the right thing using the freedom provided to them. They believe that an educated public is more likely to choose wisely and doesn't need a paternalistic approach that a conservative (who ostensibly fears the world) would take. 

The Jesuits, who for centuries were the intelligentsia of the Catholic church, tended towards liberal education and embraced intellectualism to help improve the world for the most people.

Once we understand how people think we can see why their politics align with that world view. It may not be one we agree with but at least we can now attack their reasoning from a place of knowledge.

In this light, the adoption of Trumpism by simple minded evangelicals can be understood but it doesn't make it any less aberrant or dangerous.