Agree with all this, but it may be useful to expand on some of the ways people fool themselves by aligning with a party and ideology to the exclusion of all else, with a bit of armchair psychology thrown in.
I've been having long, detailed political and current-events discussions by email with a small group for decades, mostly driven by one hard-right former conservative, now Trumper. He's all in on the Fox and Breitbart talking points, and sends out various blog posts in that vein every day. Yes, really - every day; I read most of them, just to stay in touch with how these people think (or "think," to be more accurate). I used to argue against the more ridiculous ones, mustering facts and logic and all those things that are supposed to matter, and I found it was counterproductive - when this guy is confronted with sound arguments against his team, he hardens his position. His arguments usually consist of stuff that Fox or Breitbart or their ilk made up, which are easily disproved, and accusations that Obama or Clinton or some other Democrat or random lefty did something worse - you know, the kind of stuff you see on this board all the time. I eventually realized that he literally cannot admit any wrongdoing or malfeasance on the part of his team; when I force him to see a lie that he believed, he'll deny it or downplay it (he says Trump 'sometimes stretches the truth.' That's as far as he'll go). One time I got him, in the course of defending some R initiative or other, to argue in favor of hypocrisy. After that he stopped communicating with me for several years; I think I actually made him see that he'd become exactly what he thought he was fighting against, and he didn't like it, although he wouldn't admit it.
There have been several psychological studies showing that conservatives are motivated by loyalty to their group over most or all other considerations, while liberals are at least somewhat open to rational argument. This is considered to be the main difference between the 'sides,' along with cons being driven by fear and favoring authoritarianism and established hierarchical structures, and libs being more compassionate, empathetic, and impulsive.
So the way I see it is that the hardcore Trumpers cannot give an inch on their team; once they start accepting the validity of any criticism of one of theirs, they'll have to ask themselves how many other things they have been told, and believe, that will turn out to be untrue. That's why they retreat to the echo chamber: it's not entirely the other way around, although of course there is plenty of feedback, but they create the echo chamber as much as the echo chamber creates them.