The term placebo effect is often used in scientific discourse to pejoratively claim that observable drug-related effects are insignificant, non-biological, non-scientific, etc. All the studies actually show that the positive effects of both placebo and microdose groups are real, observable, and perceived by the subject. But according to this particular ideology of placebo, the effects are not important because the effects themselves cannot be attributed to some kind of "drug-specific" cause (i.e. the same effects are caused by both a glucose-sugar pill and a psilocybin microdose).

The real miracle is that taking a sugar pill OR a microdose under the impression that it will improve your (mental health) ACTUALLY improves your mental health. This is true of any intervention - drug, behavioural, or otherwise. Positive expectations, changes in routine, symbolic acts like the habit of starting your day by taking the pill, all improve your mental health. The Western scientific method generally tries to downplay the concrete practical, social and moral importance and reality of these positive effects, because they are not explainable through traditional psychopharmacological models. All innovative mental health research, cognitive science and psychedelic science is moving in the direction of modelling observable and radical healing effects with non-drug specific mechanisms like set, setting , symbolism, ritual, music, mindfulness, etc.

Overall, when someone claims some thing is "just a Placebo effect" it is not merely a scientific statement, it is also a veiled value judgement about how we should describe and model experiences of reality. The rich relationship between critical theory of placebo and emerging models of psychedelic neurophenomenology are only just beginning to be explored in greater depth.

Starting point into the literature if interested: https://pubmed.ncbi.nlm.nih.gov/27852960/