I personally think that Greys are real, but I am not certain in the least what "real" in this case constitutes. I apologize for answering your question with a question within a question, however, there can be little question that the AP (abduction phenomenon) is the basis for that "real" specific qualifier here.
I think based on Mack's research alone that the AP consists of several specific icons with respect to experiencer reporting of interactions with humanoid aliens. The Greys being the primary one of them, with that particular icon further divided up several times with respect to reported experiencer data base correlations. Authority/Eye Starers often typically identified by larger uniform size among present Greys during an abduction, helper/watcher(?) status Greys often being diminutive in size by comparison.
I also think that Greys are synonymous with abduction reports from the mid, and distant past, such as Genies/Gnomes/Elves/Trolls/Goblins/Demons/etc.
Most likely the Greys are not material beings, but are either informational/discarnate in nature, or they in and of themselves have the ability to project as much into our native stream of interactive consciousness, remotely. Greys may not just be a representation of artificial intelligence as much as they are a cellular arrangement serving more so to collectively makeup an artificial consciousness that is used for observation by an intelligence that we never meet within the experience.
It may be that we ourselves, as is described by numerous eastern mystical doctrines, are a composite being consisting of a synchronized pairing of both physicality and information.
It could be that black matter itself is informational in nature and represents theirs, and possibly other species as well, native environment. Maybe that's why we never find any real evidence of their technology.
Either way, IMO, Greys are real. This being despite the great stigma that surrounds their ongoing culturally specific ,and therefore highly transient, Folklore image identities. We can historically confirm their protocols apart from these contextual relevances, via the rear view mirror of our culturally unhinged speculations/identifications.
Actually, if you think about it, an informational being in nature would explain what Chris O'Brien documents concerning a trickster's interactions with humanity throughout time. It would also propose a basis, or environmental platform, for such mysterious entries as are contained in the vast realm of iconic Fortean considerations. If pure willful information were to be witnessed acting out as being independent in volition within the observers consciousness, would it not seek to establish an informational relevance within the context of the experience in an effort to be identified? What else would it have in common with the other sentient being if it did not? If an informational being were to impart a mutual sentient introduction, it would have to take place within that common ground aspect of the universe that one sentient being solely dwells in, and the other sentient being half dwells in, all the time.
We are conditioned to perceptually anticipate the rational confines of our environment. Simply, if we throw a rock in the air, we expect it will fall back to earth. The merger between the two sentient, yet physically unfamiliar beings, may result in a myriad of high strangeness experience wherein the observing composite experiencer is forced to perceptively reconcile the sentient joining experience through this aforementioned anticipatory consciousness filter. The results might be likened to a form of synesthesia. But instead of perhaps hearing a color, or smelling a sound, or whatever, your mind projects random pieces of subconsciously assembled information of what it posits as being useful and self protective information to bridge this threatening irrational merger with a foreign informational sentient being.
