Sounds like you need to try out some LSD bro.
From my perspective, to put my anecdotal experience beside yours, I know many very stable, very loving, very intelligent people who use LSD occasionally. These people generally don't talk about it, or haphazardly recommend it to others. But they do enjoy the experience of altered consciousness, and the experience of experimenting with new thoughts and perspective.
If it is a damaging drug, as you claim, then these people emerge from their trips strengthened from the harm. If it has irrevocably altered their personalities, then it has done so to their benefit.
LSD, like other drugs, is a way to play. There are those who take it too seriously - this crowd are as ridiculous to outsiders as the whisky, coffee, or marijuana enthusiast. But for most, it is simply a safe and reasonable way to spend a day in leisure.
Anyway, I simply asserted that the claim to know an experience, before having that experience, is absurd. I'm pointing to the distinction between knowing something, subjectively, as opposed to knowing about it, objectively. That's just a fact.
Consider a less contentious example. Let's say that you've never eaten dry-aged beef. Would you claim to know the taste? Sure, you could understand the chemistry of the curing process. You could have loads of GC/MS data. People could tell you about it. You could have all sorts of brain scan data. You could have formulated all manner of suppositions. But even with all that, until you took a bite, you wouldn't know the taste.
In case this is a new concept for you:
> There are, however, other uses of the terminology related to objectivity. Many philosophers use the term “subjective knowledge” to refer only to knowledge of one’s own subjective states. Such knowledge is distinguished from one’s knowledge of another individual’s subjective states and from knowledge of objective reality, which would both be objective knowledge under the present definitions. Your knowledge of another person’s subjective states can be called objective knowledge since it is presumably part of the world that is “object” for you, just as you and your subjective states are part of the world that is “object” for the other person.
> This is a prominent distinction in epistemology (the philosophical study of knowledge) because many philosophers have maintained that subjective knowledge in this sense has a special status. They assert, roughly, that knowledge of one’s own subjective states is direct, or immediate, in a way that knowledge of anything else is not. It is convenient to refer to knowledge of one’s own subjective states simply as subjective knowledge. Following this definition, objective knowledge would be knowledge of anything other than one’s own subjective states.