It might be because there are people who have experienced otherwise and you seem to be speaking in generalizations instead of experience. This is anecdotal, but taking MDMA once, recreationally and not in a theraputic sessions, helped me with social anxiety.
The best analogy I can give is like you're playing a NES game, and it's glitching all over parts of the screen. You're still able to play, but there's interference that you just eventually learn to ignore, even though it is wearing on your experience. MDMA is like hitting the reset button and the glitches are gone. You realize there's a beauty that you've been missing this entire time, because you grew to view life through this filter.
Again, this isn't true of everyone's experience but studies are starting to show it's able to help certain people that can use it.
This is not my original thought, but what if that "beauty" is manufactured? What if it's not genuine beauty, but an illusion created by your mind to validate the experience of taking the MDMA? I guess the research would prove whether that's the case.
I realize that's a pretty extreme statement to make. But from what I understand, we hardly realize how the mind works. I am not saying don't dismiss the research. I just wonder if we are trying to sell psychedelics as a magic pill, when maybe just awareness is all you need.
What about people who have bad trips on these drugs? Do we dismiss them as people who aren't just suppose to take psychedelics?
I rate of people who have bad trips is very low with MDMA. You're right that it's a thing with LSD or Psilocybin. The tripping community has these ideas of "set and settings" that you should strongly adhere to. Make sure you'll be in a chill environment. Eat lightly beforehand. Don't trip if you're not already in a relatively stable spot. I think the idea is that with a therapist (or a seasoned trip-sitter?) they can help guide you out of any bad trips, bad trips being anxiety spirals or something.
Often the most important thing to reassure people who are having a bad trip is that this too will end, and they will feel normal again soon. The fear that the trip will be the new normal is a big fear.
Sometimes people are having bad trips because they are performing the introspection they've long avoided--- they're facing trauma. And in that respect, I think that having a bad trip is actually a _good thing_. Sure, you aren't avoiding what's in your subconscious, you're facing it head on. You might have a bad time in the moment, but it helps the healing process overall.
---
The idea that trips are just a beautiful illusion is... kind of flawed. Our brains are weird, and our thoughts can re-wire how our brains work. If someone is living is the cognitive distortion that they are unloved, but a trip of MDMA reminds them that there is love and unity in the world, then it doesn't really matter whether it's an illusion. Going through life with the belief that everyone is capable and deserve of love and unity and respect _fundamentally makes your life better_, especially if you compare it to the opposite distortion, where you are paranoid and wondering how people are out to take advantage or humiliate you.
I think that MDMA is more about breaking down cognitive distortions with a temporary "well what if PLUR??" thought experiment than it is about just creating an illusion.
I can't speak for everyone, but psychedelics really help one internalize that beauty is perceived. Everything we experience is through a perception filter.
Psychedelics are an effective means of clearing the filter of all the constraints a person accumulates in the course of life. Culture, society, education, religion, it all serves to build the filters up.
If one finds beauty in the world under the influence of psychedelics, in my experience it tends to persist long after the drugs have left the system.
Beauty in this context is interpersonal relationships that I had been missing out on because of the filter that social anxiety was creating. Sorry if I wasn't more clear with the analogy.
What if the ugliness that people who experienced trauma see isn’t real either? Everything you experience is an illusion created by your mind, sober or not.