Section A - Introduction
We live in a scary time. In the future, people will spend a larger part of their lives online on a scale never seen before. Internet echo chambers will move further and further away from the realities of real life as many of their members will be permanently online and only exposed to the "reality" they find in said echo chambers. What is normal will become abnormal and what is absurd will become the new standard of things. People's insecurities will become the driving force behind this new "era of delusion".
I would like to give an example of this new phenomenon of internet delusion. The following post was published in the subreddit "twoXChromosomes":
I will critically dissect this post and some of the comments written below it.
Section B - Some Facts
Before anyone speaks of delusions, one should first establish that the opinions spoken in this subreddit are actual delusions and not fact-based statements. I will provide some facts in this section which will give important context to the later sections.
Studies show that men perceive younger women as more attractive.   In fact, I'm not aware of any studies that contradict this result.
This preference for young women seems to be universal and is expressed in many different cultures. 
The older men get, the younger they want their potential partner to be relative to their own age:
"Our results show that age preferences essentially shift with age, but in different ways for men and women: Whereas men increasingly prefer younger women as they age, women’s age preferences become increasingly diverse." 
"[...] both 20-year-old and 49-year-old men both cite women aged 20 as what they find the most attractive. The age of a woman men find most attractive never makes it above 24." 
Now it could be said that these study results are unreliable because they are only based on self-reports. Men may say they prefer younger women but are insincere in some way. After all, most 50 year olds are not dating 20 year olds. But this notion is false:
"Both young and old men say that they are sexually attracted to young, fertile women, but older men tend to marry older women, including those who are peri- and post-menopausal. We assessed men's freely revealed preference for their mates' age using an unusual marriage phenomenon in South Korea: the practice in which men purchase their brides from developing countries. Presumably, the men's mate choice, at least regarding the brides' age, is unrestricted by women. We analyzed all first marriages reported in 2010–2014 in South Korea and compared men who married Korean brides (N = 1,088,457) with those who purchased their brides (N = 45,528); the age range of grooms and brides was 15–59. While the former exhibited the typical pattern where older men married older women, the latter, whether young or old, always married young, fertile women. This finding is consistent with men's stated preference for young, fertile women in mating and suggests that the typical pattern is generated by women's limiting role in mating." 
It is often said that partnerships with large age gaps are not in the interest of both the male and female partner. Alleged irreconcilable differences in life experiences and the exploitation of the less mature partner are cited as negative. That's not true either. In fact, partners in a relationship with large age differences (more than 10 years) are happier than partnerships with no or only a small age difference (i.e. less than ten years). 
In summary, the following can be said:
Almost all men prefer younger partners, so this is not an abnormal preference.
Even old men still prefer younger partners.
These preferences seemed to be universal.
Men make these preferences a reality if they have the opportunity to do so.
Partners with larger age gaps are happier together.
I do not think that the facts I have listed in Section B require scientific evidence. They are all seem self-evident to me. Twenty years ago anyone who would questioned the higher attractiveness of younger women would have been laughed at. However, as I pointed out in Section A, we are in interesting times and therefore scientific evidence is needed.
 Finding your Soulmate: Homosexual and heterosexual age preferences in online dating (2015), Personality and Social Psychology Bulletin
 How Sexually Dimorphic Are Human Mate Preferences? (2015), Personality and Social Psychology Bulletin
 Sex differences in age preference: Universal reality or ephemeral construction? (1992), Behavioral and Brain Sciences
 The Gendered Dynamics of Age Preferences – Empirical Evidence from Online Dating (2011), Zeitschrift fur Familienforschung
 Dataclysm: Who We Are (When We Think No One's Looking), Christian Rudder
 Men's revealed preference for their mates' ages (2017), Evolution and Human Behavior
 Why couples with big age gaps are happier, despite the social disapproval, ABC
Section C - Lapsus Linguae
I picked this particular post from TwoXChromosomes because I believe the author involuntarily disclosed her true motivations. Let's take a look at the post:
The whole leonardo dicaprio thing (especially the responses) have me so paranoid it’s not even funny.
The amount of men (and some women…sadly) I’ve seen over the last few days saying it’s reasonable to ditch women around the age he does with his chicks (26, right?) is mind blowing??? What the shit. Of course there had to be men chiming in saying the old “beyond their prime” bs. God, I really thought this was getting better and people, mostly men, wouldn’t age shame as much…
Please tell me this isn’t most guys? And it’s only the incel types…? Wishful thinking, I guess. This shit is why I’m 21 and feel like I only have a few years left of being desirable to men…when I see them on social media calling girls over 24 attractive I’m shocked. How sad is that?
Sorry for such a whiny rant. I’m so disgusted by it.
The author is clearly in emotional distress because she's heard stories that Leonardo DiCaprio "discards" anyone over the age of 25. Why does this story create so much insecurity and negative emotionality? Why does Leonardo DiCaprio's personal life affect her own sense of happiness?
This anger and bitterness springs from a sense of entitlement to male attention which many women harbor. They feel hurt because such "age discrimination" damages their self-esteem and provokes the feeling of undesirability.
Section D - Hate and Bitterness
Even more interesting than OP's post are the many comments that were written under her post. A toxic mix of bitterness, insecurity, tribalism and mendacity is reflected in these comments. I ask my audience to keep the points I made in section B in mind while I go through some particularly insightful comments.
I think it's just the pedo incel types who like women so young they're easier to control. I'm 36 and have no trouble attracting men despite being 'old' according to these buffoons.
Women age like milk, ie we turn into a lovely mature stilton with plenty of taste
Unfortunately, it's not just the "pedo incel types" that prefer young women, it's (almost) all men. A clear example of delusionary thinking. The author of this comment attacks the men who discriminate in their partner choice according to physical characteristics, I think it's out of a feeling of bitterness. Despite the inaccuracy of the comment, it is positively upvoted because it presents a comfortable alternative reality which temporarily minimizes the insecurities of these women.
The following 5 comments have all a similar content. It is said that men who prefer younger women have a number of negative characteristics and represent a lower class of men:
Because of a deep seeded sexual insecurity. They love the idea of someone to break in because they are so limited in sexual experiences and they can take advantage of that girl's inexperience. Basically can't disappoint a girl with no expectations.
Leonardo is mentally stunted, he is still a child in his own mind, he is an outlier not a norm.
The only men you will stop being desirable to is men looking for their next victim.
[...] Especially these men, yikes. Imagine being worried that you won’t be attractive to the creepy 50 year olds chasing after women 30 years younger than themselves. Good riddance.
[...] Normal men find women their age attractive and men who don't you don't want anyways sistah so be glad they weeded themselves out.
Of course, this is a delusionary notion, since such beauty ideals are universal and are not limited to a certain class of "creepy" men.
The creeper defense force came out swinging on behalf of Leo, but most of their arguments have been short-sighted.
They've said nothing about his repeated treatment of women as disposable objects. They haven't acknowledged the sexist and ageist notion that women are "expired" after they become older than 25.
In a rational world, the free choice regarding association of adults would need no defense. Most partnerships don't last for a lifetime. As far as I know, Leonardo never made a promise of lifelong commitment. The author of this comment seems to think that Leonardo's personal life choices are in need of her approval. A typical femcel mindset manifests itself here, fears of being replaced in old age create this attitude. I think the phenomenon of insecure women trying to limit male agency is an example of female mate guarding behavior.
Then there are a number of comments (mostly from males) that say exactly what the insecure women of TwoXChromosomes want to hear. Here some examples:
I second that. I'm a 24 yo male. But hell no, dating girls between 19 and 24 is a pain in the ass. Not joking. Cannot handle that kind of person. Very few exceptions. Found my self dating girls between 25 and 30. Is a very clear and straightforward communication. Less drama. Less everything bad with relationships with younger women.
I'm 28 most of my guy friends refuse to date anyone younger than 25. My really good guy friend just went on a date with a 23 years old said it was the worst dating Experiance since college. He normally dates older women. I would t worry about it, the guys you wanna date don't think like that. The guys who do think like that arnt worth dating.
Yeah. I’ll say with all seriousness that the best part of being a man in his 30s are the women in their 30s.
It seems like in cases where you see pictures of celebrities in their late teens vs their 30s, they are more attractive in their 30s. This is true for both men and women.
These comments help to cope with insecurities but in an unhealthy way. They create a false perception of reality and are a good example of how internet echo chambers can systematically mislead people. People can freely choose the content they want to see on social media, and it's easier to surrender to comfortable lies than face the hard reality. So it should be easy to see how such echo chambers out of touch with reality can arise. Things that sound comforting , even if they aren't true, get up-voted, things that are true but not suitable for coping purposes will be down-voted. Most of the time, however, such messages which convey hard realities will not be given the opportunity to be down-voted because mods will ban such comments before many users see them.
And here lies the danger of these echo chambers: a separation from reality, a normalization of the abnormal and a radicalization of the members all driven by insecurities. In the future, most human interactions will take place online. This new brave world will bear many strange fruits.