We must distinguish between policy and principle.
In a society where there is agreement on basic principles, public debates will focus mainly on policy. Policy, while less abstract than principle, is in a certain sense less tractable in a manner analogous to how mathematical proofs are more abstract yet more tractable than verifying empirical claims, like knowing whether there are an infinite number of primes versus whether there's a teapot orbiting the earth.
Good policy requires a more conspicuous application of prudential judgement, which entails the integration of information and opinion of varying trustworthiness to make a best effort decision, which is something a person must learn and develop.
But one thing that is characteristic about our political predicament is not disagreement over policy per se, but the reasons for our disagreement. Two people sharing the same principles can still disagree about policy, and because they share the same principles, a debate over policy is manageable, because the basic parameters circumscribe the debated subject matter. However, if you look closely to the policy disagreements we're seeing, it is clear people are talking past one another. Something deeper, unspoken, is at issue. That is because the agreement on matters of principle is shrinking. This is why some view today's disagreement in terms of religious warfare, because in a sense it is.
As I've written many times in comments on HN, "religion" is effectively just a synonym for "worldview". Many people have ad hoc and incoherent or strangely specific or even parochial intuitions of what religion is, but understood as a bona fide or coherent category, it is essentially just another word for worldview. Everyone has one, however implicit, so it isn't a question of whether you "have a religion", but which. You may not realize that you are subject to a worldview, just as the proverbial fish that has never left the ocean doesn't know what water is, but it's there influencing your decisions and the course of your life.
In the US and much of the West, this has generally meant liberalism. And we're all liberals. The right and the left? Both liberal. The conflict between them is less Hindu vs. Muslim and more Pharisee vs. Sadducee. But as time progresses, as the internal tensions of liberalism unfold within the human psyche and within society across time, as liberalism crashes in slow motion because of this dynamic, as the proverbial idols enter their twilight, the conflict can only deepen. And it won't be a left-right split per se.
Some miscellaneous remarks...
1. The author makes similar observations w.r.t. religion. For example, he notes that "[d]espite organized religion dropping in attendance, religious patterns of behavior are still everywhere, just adapted to a secular world." Absolutely. And this includes Silicon Valley ideology, which is just a variation of Americanism. You see plenty of "religious patterns of behavior" in SV (though I sense we are past the heyday of peak salvific SV eschatology; maybe it just has a different character now, unvarnished and naked).
2. The author's view of religion is nonetheless tendentious and rooted in stereotype and trope. For example, the history of martyrdom in the Catholic Church alone demonstrates that "going along to get along" or mob mentality are opposed to the Christian view of truth above all else. God Himself is taken to be the Truth, and Christ the incarnation of the Logos. The authentic Christian ethic, despite the dishwater often passing as Christianity, is morally austere in this regard, hence preferring to die for the truth (literally, as in "red martyrdom", or by suffering injustice, so-called "white martyrdom") than to betray it. Lying is categorically impermissible. Life is to be found only in the truth; only spiritual death is to be found in lies. Better for the body to die than the soul to die.
The notion that religion is about group cohesion even at the expense of the truth is certainly not a feature of Catholicism, but a common human tendency that it attacks, even if individual Catholics or groups of Catholics behave otherwise (again, a common human tendency). There is no authentic unity or authentic love outside of the truth. You cannot love what you do not know, and a society united in a lie is deficient in unity to the degree that the "unity" is rooted in the lie.