I'm convinced it's genetic. Like gender, we are divided evenly in half. And it's not completely binary...just like gender. As our ids are matriculating in the womb we become conservative or liberal just as we become male and female, just as our sexual preferences are innate, formed before we leave the womb, not taught and not subject to change.
Our competitive nature makes us automatically choose sides and it has made us the most dangerous species on the planet. It's not a bug, it's a feature. It's not mental illness any more than homosexuality is mental illness. They can't imagine being any other way and they think we're the crazy ones. As long as certain subjects are never breached, then we can get along fine, we don't need to agree to work together or to be friends.
But these QAnon folks...Jewish space lasers? Pedophile cannibals? These folks are genuinely broken. By a society that moves too fast. It's not the first time in our history that religious fantasies have superseded reality. They have fallen prey to the sinister ministers and have fallen under the cult like control of those who would profit from them.