There’s always the possibility that our brains filter out aspects of reality for the sake of our sanity, or for some other unknown reason, and that these drugs lift the filter, so to speak, which is also proven to be true to a degree, like how shrooms sort of break down established beliefs/definitions and understanding, and I suspect that phenomenon is probably being misconstrued or inaccurately extrapolated on to assume the filter is about seeing something extrinsic about reality and not just revealing the internal processes of our minds.