Because at the point where people browse these forums, they are so desperate they will try literally anything, and are surrounded by people who feel the same, and a lot of the things being reported cannot possibly work, are extremely tied to very specific conditions, and possibly very dangerous. People will also select the meds they hear people report cures of in ways that emotionally resonate, not because there is good evidence it would transfer for their case, or at least be safe.
Because at the point where people browse these forums, they are so desperate they will try literally anything, and are surrounded by people who feel the same, and a lot of the things being reported cannot possibly work, are extremely tied to very specific conditions, and possibly very dangerous. People will also select the meds they hear people report cures of in ways that emotionally resonate, not because there is good evidence it would transfer for their case, or at least be safe.