The problem is we are talking about something that is orthogonal to the effect. An example is more like getting prescribed anti-depressants for back pain. I hear it helps with the pain, but you are getting personality alteration as a side effect with it.
Like if im suffering pain, I don't want to get drug-induced quasi religious epiphanies from psychedelics. I Just want the pain managed. And what's really annoying about LSD is how it keeps getting promoted as a wonder drug here.
What happens when docs start prescribing it for back pain too?
It's not just about pain management - it's about accepting and making peace with dying. If there's a possibility that a drug can make this process easier for terminally ill patients, why would you object to its use by people who choose it?
All things are bad if not taken in moderation.
My experience (personal and thus merely anecdotal) on mind altering drugs has been only positive.
My SSRI medication was very welcome when I needed it, and I am very happy they 'altered my mind' and helped through some very dark times.
If I was hit by depression again I would not mind trying a psilocybin based medical regimen.