I like it. There's an easier answer to "why don't people move from tribe to view". It's because it's painful to question one's own beliefs, and that's how that change happens. In fact such a move appears masochistic to many, since it almost never pays to undermine loyalty in favor of principle.
I hypothesize that we're seeing the influence of the legal system on the public turbo-charged by Citizens United money. An attorney is paid to be a "zealous advocate" for their client. This means never spending effort on anything that might be against the client's interest. Self-reflection is stochastically against their interest, so why even risk it? Considering alternative views might be against your interest, so why risk it? Therefore, in this new zeitgeist, such behavior is not just perverse and painful, but even unethical and wrong.
The problem, of course, is that for this system of adversarial argument you need an impartial judge. In theory that would be the public, but it turns out flooding people's minds with unethical lawyer screed 24x7 turns more people into lawyers, not judges. "The world is changed. I feel it in the water. I feel it in the earth. I smell it in the air. Much that once was is lost, for none now live who remember it." This could very well refer to the value of dignity, honor, integrity, fairness in debate, respect for one's opponents. These are always under assault, but in the last 10 years they have been decimated to the point people don't remember they ever held sway and young people don't know what politics was like when they did.
"since it almost never pays to undermine loyalty in favor of principle"
nailed it imo, thanks for reading!
.. "we will need writers who remember freedom" Ursula Le Guin
Both of our best ways at getting to the truth - Journalism and Science - rely on entertaining and following all sorts of contradictory ideas and then comparing them with observed reality.
Universities in particular need to be physically safe spaces, where ideas of every kind can be mercilessly attacked.
We are losing what took so long to build.
They become too entangled with identity. The advantage of holding one's identity loosely, and attributing it one's actions, is it facilitates changing one's mind about certain things, or updating beliefs in increments.
Challenging your own viewpoints is not just hard, it's downright dangerous. You can really lose your sense of identity and question your own morals if you are not well-grounded. It's much easier to dig your heels in and try to limit your self-reflection to be more "safe". (I still think you should question your viewpoints, but I don't blame people for being a little afraid.)
This is especially true if you have a history of being somewhat cruel to people on the basis of a conclusion you're not really 100% sure you agree with anymore. Now if you question it, you have a lot of guilt to contend with.