LSD is nothing more than a serotonin receptor agonist (although LSD has a bit more dopaminergic response than other serotonergic psychedelics). It produces certain effects in the body. That's it.
The evidence of long-term harm for careful use seems low to me. (There may be a potential risk of schizophrenia / paranoia disorders and similar, though from what I can Google there is nothing conclusive yet. So if anything, that's what you monitor for. Even in the worst case, I would doubt that a single use would trigger this.)
That certain kinds of psychedelics (serotongerics in particular, but also NMDA receptor agonists, such as the naturally occurring ibogaine... and maybe a few others) seem really prone to produce this sort of almost spiritual response actually fascinates me, for exactly that reason alone. I wouldn't call this "spiritual nonsense" "fake" per se. Maybe these molecules in reality are clues to the actual mechanism behind the emotion, right?