High self-esteem.

Our world is an extremely interesting thing, don't you think? In essence, we know less about it than we would like, but we can still say something, namely that it contains an immense amount of information. And for everything we don't know or know ambiguously, we can formulate a huge number of hypotheses, and only time will tell whether they were correct or not. Well, and common sense plays a role somewhere. Let's take the origin of the Universe, for example. There is the classic Big Bang theory (and at least two interpretations of it, which differ in some ways), and there is an interesting ekpyrotic scenario (although the term "Big Bang" is used there too, but the scenario is completely different). I personally like this idea more, although it is often criticized, but time will tell.
But the most interesting thing is to observe how people, or rather, the majority of them, perceive this world. Let's take the same example of the Big Bang. Do you think that most people, upon hearing this news, immediately began to actively discuss the paradoxes of the hypotheses and ways to resolve them? I have a different impression. Well, at first, the hypothesis was, of course, criticized, as it should be, but I won't claim what happened in the meantime, but at the moment, in my opinion, quite a few people form two camps: in one, it is asserted that the Universe was created by the Big Bang, and creationists are losers, and in the second, it is said that scientists are fools and all this is nonsense, and continue to write fairy tales about things that you have not seen. Although it should be noted that there are still many people who do not belong to either of the camps for one reason or another, but still... The particularly ardent supporters of absolute materialism and the particularly ardent supporters of absolute creationism are somehow more noticeable; they will not fail to insert their very necessary and useful opinion if only the opportunity arises, and the rest can only be heard in special situations and in special circles. So, in the end, it creates an obsessive impression that stupidity rules the world, and this impression is probably not entirely false.
And that's exactly what happens. Any topic that the masses consider relevant immediately gives rise to two opposing camps. Like the Tories and Whigs in England, if only the supporters of the former and only the supporters of the latter, most Englishmen probably vaguely realize that there are a dozen parties, only those that are currently represented in parliament.
But there, it doesn't really matter; England is not in dire straits, or at least not more than others, but there are really important issues that always give rise to two camps. And, apparently, this is only exacerbated by modern media (print, television, and now the Internet). Why two? What a strange number that persistently haunts us everywhere? Is it because someone wants to use each side in their evil, selfish, and mercenary interests? Well, probably, that too. But I, being a relative optimist, see the main factors as something else. The first is the syndrome of sleep or a wild beast. I read somewhere that a characteristic feature of wild animals is their inability to engage in self-dialogue: they are capable of thinking, but they are not capable of changing their opinion about what is happening, let's call it that. If a wild beast decides that it has prey in front of it, it will begin to hunt. It will not stand and think, maybe this is a hunter's trap? It will realize that it was a trap only when the trap clamps down on its unfortunate paw, but it will be too late...
The same is true for a person in a dream, when his mental process goes somewhat differently, the mind is weaker, and so on. The first version that comes to mind, having passed a minimal check by consciousness, is a priori true. Everything that happens next is, at best, perceived as an argument in its favor, or it is completely ignored. Surely, everyone has experienced this, that some real factor (like the ringing of an alarm clock) is perceived in a dream in a slightly different way; those who have experienced it will probably agree with the previous sentence. The ringing of an alarm clock is perceived as a signal, knights rush in a crowd to the wall to defend themselves from the Moors who are besieging them, and even a frankly futuristic car horn on the street is unlikely to immediately convince us of the reality of what is happening.
So it is with people. Television/the Internet/neighbor Klavdiya provides them with a version of what is happening, and all that the humanoid has to do is argue it, although they a priori consider it true, and the arguments are just to make themselves look smart. And the arguments themselves are often borrowed from the same sources, although some particularly chosen ones may not even bother with them.
In my opinion, this fully explains the limited number of versions of everything in this world, right? Or rather, the limited number of popular versions. Although it is still unclear why there are only two of them, and not more. Or less... The second seems even more preferable in this model; it would seem that everything should simply "annihilate" into it. But no, there is still some other factor.
The essence is that people are always dissatisfied with something. The reasons for dissatisfaction can be different, sometimes less serious, sometimes more. So, once upon a time, the proletariat, who, together with their wives and children, had to work 15 hours a day, were forced to fight for their rights, and a little more than half a century later, a pampered bunch of "intellectuals" decided that they knew better which path one European state should follow and, out of nowhere, staged a revolution, a civil war, and ended up either abroad or in concentration camps (or about half of them). Be that as it may, the search for the guilty always gives its results, whether they are invented or really have a reasonable basis. And here we come to our favorite number, because it is obvious that the "guilty" themselves do not consider themselves as such, and most of them have a symmetrical reaction, directed, you think, where? Well, of course, to the first side that comes to their mind, namely, to the one that is exactly opposite to the first, so that they can deny all possible and impossible arguments and come up with new ones in their defense. And the first point of view is also not a fool and will vehemently try to refute everything that the second tries to say. And so it goes. The scenario is quite classic and repeats itself again and again, in different parts of the world, with different people, but that's how it is...
And only somewhere on the sidelines, quiet and calm adequate people are waiting for their time, who are not going to shout in the streets, in newspapers, on television, and on the Internet that the first are geniuses, and the second are all idiots. Or that the second are geniuses, and the first are accordingly idiots. But those who understand that everyone is an idiot, because the struggle is not for the right point of view, but for the first one that comes along, the one that is popularized. A fight without rules, where any means are good, especially deception and self-deception. And that the only correct point of view is the one that comes from true premises, and not when the premises come from opinion. It is necessary to accept and take into account everything that seems logical in itself, moreover, newly received information can and should dynamically change and correct the conclusions that follow from it. And not to dismiss it as useless, or "refute" it artificially.
I am an optimist, and I believe that there are even many such people, they are just quiet and inconspicuous, and no one is interested in them, because here everyone considers himself a genius, even if he shouts that green is white, or that green is black. But someday people will realize it, they will look for those who can call green green, and they will find them. I am still an optimist.

P.S. Sorry for the long text.