The full quote from that para

> We like to believe that we form our opinions by gathering evidence, weighing facts, and arriving at reasonable conclusions. Be for real. No we do not. Here’s how it actually goes: We form an emotional impression first, then we build a belief around it, and then we go looking for facts that support it. This is my theory as to why we’re so divided in this country. Beliefs built on emotion are nearly impossible to reason with.

This idea is explored in depth in The Righteous Mind: Why Good People Are Divided by Politics and Religion by Jonathan Haidt.

And related David Hume quote:

> Reason is, and ought only to be the slave of the passions