Wow - you have written this with palpable zest! Electric! Thanks so much, enjoyed reading.
My take on this is based on Jonathan Haidt's excellent book - The Righteous Mind. We are essentially intuition-driven information processors, constantly scanning the world around us, morally interpreting information and colouring narratives with our unique worldview. A liberal worldview pegs a conservative as a traditionalist, xenophobic, capitalistic, flag-waving, tax-dodging, climate change denying, warmongering, pseudoscientific, Churchgoing, anti-vaxxer incapable of rational thought. Whilst to the conservative, a liberal is a virtue-signalling, tree-hugging, anarchist vegan gay snowflake citizen of the rainbow-world. We readily allow intuition to lead us and then use our rationality to come up with evidence to support our beliefs - the absolute arse-backward way it should be.
I'd really appreciate if you could read my article and feedback - the parallels between your take for WHY we are so divded, enraged and partisan and HOW our brains are literally wired to be this way according to Haidt, are uncanny.