Most positive anecdotes are not nearly as extreme as this one, but there's certainly skepticism for even mild positive statements.

You can look in the comment section for this very article for multiple examples - I replied to someone who indicated that another person must have "depressing" nights because they stated that they sometimes enjoy having a night with friends listening to music while high, for example. Subjective opinions of how to enjoy an evening are greeted with being told they're wrong - a bit beyond even skepticism, even!

If us potheads start posting anecdotes about how smoking took us from being unsuccessful and contemplating suicide to successful and having wonderful personal happiness and contentment - basically the reverse of the original post in this thread - I'm sure we'd see similar levels of skepticism. As it is, the positive anecdotes are basically "It's fun and helps me relax", "I feel more creative while high", "It sometimes helps me approach things from a different perspective" and similar.

I've had the same reaction from sharing a story about bad experiences with mushrooms. It wasn't in the context of evidence either, but still got people saying it sounded like anti-drug propaganda.

I think it's just the result of a cultural perception shift swinging hard the other way from the decades that drugs were demonized to now people looking at many drugs (mdma, marijuana and psilocybin especially) as miraculous substances that will solve all our issues. This happens with most shifts - it starts on one end of the extreme, then gets a reaction which swings the pendulum to the other extreme. In a decade I'm sure it will even out and we can have open conversations without reactions being so dogmatic.