Human consumption of a naturally occurring mushroom (food) that happens to contain psilocybin is absolutely a natural occurrence and as a result has a history of human consumption older than wine.
> Human consumption of a naturally occurring mushroom (food) that happens to contain psilocybin is absolutely a natural occurrence
Same could be said about death cap mushrooms. Something being natural or even being occasionally ingested doesn't make it any better. Natural, occasionally ingested organisms can kill you on the spot.
You have canine teeth for eating meat instead of tree fruits. Your body can also extract nutrients from this fungus versus merely passing it like if you ate some wood or something else entirely non-nutritious. You might be one of those people who are able to process lactose effectively. None of these things are unnatural to our species if we have natural mutations in our population that confer these adaptions.