Constance, i agree with a lot of what you wrote.
In that specific dmt example, an isolated one at that, it seems that the indivudual's pursuit of a rocketship high led him to an experience he personally connected to the Heaven's Gate crew, my own Ufological nemesis. Yes, drugs expand consciousness and create intensities of feelings very difficult to forget, but not all things found here are truths. I advocate meditation before drugs to explore or to heal. And btw some meditators also report "alien" contact. So before I would reach out to telepathic communication from unknown entities as the source I would look more closely at the commonalities that go along with certain experiences taking place inside the common, finite territory of the cerebellum and our society. I like John Mack's work over Hopkins' but would debate the source of the internal experience still.
The experience of seeing different types of aliens (reptilian, greys, Nordics etc.), elves, dwarves etc. appear to have socio-cultural connections, as do even the different kinds of ships seem to be tied to different geographies and points in time. I've often thought that what we see, think we see, or hallucinate, are very much tied to the nature of the stimulus and its interaction with our own culturally programmed, or frontloaded, experiences.
If we could separate the witnesses of nuts and bolts craft from the experiencesrs of ayhuasca I would argue that what they are seeing has everything to do with the drug and it's specific effects: again examples above include goblin acid & e.l.wisty's reference to a common substance that routinely produces violent imagery for the experiencer. So it's not really about an external agent, but an internal effect tied mostly to the chemistries involved (brain and drug interaction) and the socio-cultural parameters of the experiencer. Set and setting define much of any hallucinogenic experience.
Consistency in DMT then is about its chemistry more than anything else. The reporting of a vision as a substantial reality being experienced is not about stepping into an actual dimension IMHO but all about the same feelings one has upon waking up from a dream that features many familiar faces from the real world and in an environment that felt real, and so we wake up often with the same feelings as if that dream really did happen. Some dreams have impact for days, months maybe; some are even unforgettable. But just like powerful drug induced experiences, it does not mean they are real, no matter the emotional intensity or conviction the experiencer brings to the table. It's still an entheogenic fabrication. No telepathy at all.
What I agree very much with is the opportunity to see an interconnectivity or even an understanding of certain processes, or perhaps even hidden knowledge, that may come out of the hallucinogenic experience. It certainly allows people in some cases to eradicate the veil of consumer society & see through notions of pretense, fabrication and some of the junk we've all been brainwashed with. Some people do this by thinking it through, meditating, and others take mushrooms and are then allowed to remove the traditional anxiety that mortality brings to us. Others though may stumble directly into a rearrangement of reality, and contrary to some above posts, I do know people who walked through the doors of perception and then could not walk back through; because, their mind got rearranged by the drugs permanently and they have never been the same since.
As for personal, carefully planned research into ayhuasca, I see this as a positive if it is a positive for the person choosing that path and who am I to say otherwise. That's what free will is all about.