I think I'm making two assumptions here, and they explain the bulk of our disagreement.
First my intuition here is that in most situations, we should expect any specific example brought to our attention to be actively misleading. Out of thousands of stories about LSD, this one happens to be on the HN frontpage- should we not expect it to be unusual in some way?
Second, I think I assume that for any given activity, there exists at least one story about it that is very bad. So finding such a story shouldn't swing your judgement too much. It isn't new information!
To put it another way, we can't possibly be using the pair (average case gain, example very bad outcome) to judge if things are worth it. When we decide to cross the road, we are drawing on our extensive record of safely crossing roads, as well as our highly accurate model of the road (I would feel much less safe crossing a highway at rush hour than a suburban road at 1am) to judge the situation. If we just drew on benefit (get to the other side of the road) and potential cost (get hit by car), there would be no difference between crossing at an intersection and jaywalking. Clearly there's a probability component which is not drawn from the ether, but instead from our internal model of how the world works. I think that in your argument, this would be the "healthy dose of common sense".
In the case of drug effects, or in medical interventions overall, we don't have that benefit. Here anecdotes and common sense commonly steer us wrong- that is the undeniable conclusion of decades of disappointing research.
My specific disagreement with the way the author framed their point, which prompted my response, was how they felt that people who have had good experiences and talked about them were "naive", because the author themselves had a bad experience. I take the perspective that those people are no more wrong than the author- both are generalizing entirely from their own experiences. But your perspective would seem to argue that those people talking about how LSD is great are correct! After all, many psychonauts have tried LSD many times and come out fine, and have seen others do the same. They are reasoning from anecdotes and a healthy dose of common sense.
It may well be the case that for most peoples' risk budgets, LSD isn't worth it. The author obviously things so. But at no point do they make that argument! The sum total of the post is "Some people anecdotally say they get great benefit from LSD", "I had extremely negative effects from LSD (as do some other people)", followed by "therefore LSD is definitely not worth it for anyone". Huh? It's totally understandable why someone who went through what the author did would feel this way. It would be entirely unreasonable to expect someone bitten by a shark to couch their very real and very bad lived experience with the statistics on shark attacks. Hell, there's a legitimate point to be made about how the spiritualism and hype around psychedelics mean that positive anecdotes are treated as data while negative anecdotes are brushed under the rug. But the author, however understandably, did not make that point.