Did you ever wish you could buy liberals for what you know they're worth and sell them for what they think they're worth? A common theme among progressives is that conservatives aren't just wrong, they're dumb. Reagan was dumb. G.W. Bush was dumb. Trump is dumb. "Knuckle-dragger," "mouth-breather," "stupid" and "uncultured" are typical pejoratives hurled at conservatives, who apparently tend to live in trailer parks, require dental care, handle snakes and marry first cousins. Why, I had a liberal actor (excuse the redundancy) tell me once that I wasn't necessarily bad, just not as "evolved" as he was. (I had a great retort at the ready, but decided to just lash him with my tail instead.)
The reason for this arrogance isn't as simple as many may think, as it relates to a deep psychological phenomenon that makes it difficult for those afflicted to evolve out of the leftist primordial soup.
I'll introduce this with a story. Many years ago I was at an affair attended by a very chauvinistic, left-wing Greek fellow who would expound upon the superiority of Greek culture while at times demeaning the U.S. He was like the father character in My Big Fat Greek Wedding, only with an anti-American twist. Desiring to take him down a peg and do a little face-to face trolling, I finally said with a smirk, "If all that's true, why is Greece now like a Third World country?" (For those offended, know that I have great respect for ancient Greek accomplishments, just love moussaka and have the physique of a Spartan hoplite.)
Well, I exaggerate not when saying he turned red and, with veins popping out in his neck, exclaimed, "Don't say that! Don't say that!!" It was the kind of situation where you get the feeling the guy might take a swing at you.
His intense reaction wasn't hard to explain. His self-esteem, his self-image, were wholly dependent upon the idea that he was a member of an elite, a superior group, with which he identified so closely that there was little to no separation in his mind between it and him. This was something deeply ingrained, part of the fabric of his being. Thus, any challenge to this idea struck directly at an intractable self-image, threatening to upset his ego's world order, which had him, through group association, at its very pinnacle.
This phenomenon is common. It's often exhibited by those considering themselves part of a "master race" or any kind of special group. It can be very comforting: A person may not be very accomplished, intelligent or gifted and might otherwise feel quite inadequate. But his group association saves his psyche's day, for whatever he is or isn't, at least he's not like those other people, those untouchables. What this means is that the claim to superiority is often a cover for feelings of inferiority.
Remember that at issue here isn't a mere intellectual appreciation. For example, I truly believe Western culture (which did originate with ancient Greece, mind you) is superior to all others. Yet I derive no self-esteem from being a "Westerner"; it's just not part of who I am. Rather, the phenomenon in question here is a deeply emotional one.
For this reason, it's wholly resistant to intellectual appeals. You can't logically talk someone out of something irrational on which his self-worth is entirely based. In fact, if it begins to dawn on such a person that his notions of superiority — and hence his self-image — rest on a lie, it will be intensely painful and depressing. The individual will thus have a strong incentive to rationalize this realization away.
I don't claim that every single leftist derives his self-esteem from the notion he's part of a superior group called "liberals," nor does this phenomenon completely explain leftist resistance to reason. But it is common among devoted liberals, and it's part of why, as a group, they can't give traditionalist views a fair hearing. Doing so doesn't just threaten their ideology; it threatens who they are, their entire self-image. Any argument that may give them even an inkling they may be wrong can induce a bit of panic and is thus quickly rationalized away — often as the rambling of uneducated, un-evolved mouth-breathers who just don't know any better.
This phenomenon is exacerbated by two related factors. First, liberals are generally dysfunctional, vice-ridden people who embrace what we call liberalism because its underlying moral relativism/nihilism helps them justify their sins (they become the arbiters of their own "values" — "Everything is gray, a matter of perspective. I have my own 'truth'"). Simultaneously, liberalism allows these virtue-bereft people to virtue-signal by paying homage to the day's fashionable values. In other words, liberals are generally morally "unaccomplished" people who often have nothing to cling to but the illusion of intellectual, and often moral, superiority.
(As to the left's actual moral inferiority, I urge you to read the excellent 2008 piece "Don't listen to the liberals — Right-wingers really are nicer people, latest research shows.")
Second, conservatives are more likely to have authentic faith while liberals tend be to avowed or de facto atheists, which is why church attendance is one of the best predictors of voting patterns. This has an effect. Theists may, and hopefully will, recognize moral differences among people and groups; any tendency to become haughty, however, is often tempered by a divine injunction prescribing humility and the knowledge that we're all sinners, part of a fallen race. Love for others is also demanded. But atheism involves no such requirements; in fact, its correlative moral relativism/nihilism (explained here) makes "If it feels good, do it" the ultimate guide for behavior. Moreover, unable to look up at divine perfection, and with the individual becoming his own source of (pseudo) "morality," the self is often exalted, the ego deified. Like a pharaoh believing he's a god on Earth, it then becomes easy to look down on others.
Just as liberalism is defined not by an unchanging set of doctrines but by opposition to conservatism and what it defends — the status quo — godless liberals can only judge themselves relative to other people. And being moral train wrecks, they can't really be happy. But, hey, whatever they may or mayn't be, Mr. Conservative, at least they're not you. And that's one status quo they're dead set on maintaining.