Some people, for whatever reason, tend to distrust science and its cold, hard, evidence based facts. Humans like to believe that they're special, even spiritual, beings and that all that "medicine" stuff is just a little too clinical for their special snowflake soul.
Alternative medicine has a much fluffier public image, with its associations with the mystic east and emphasis on just how special you are.
If you're lucky, you'll be handed a crystal and have your aura poked for a bit until you start to feel warm and fuzzy. If you're unlucky, you could end up in a whole lot of pain, trouble and financial difficulty.
Unlike real medicine, alternative medicine is not subject to any testing, regulation or trial. This essentially gives snake oil salesmen carte blanche to sell you anything they like, even if it will actively hurt you. Alternative therapists have never taken an oath to "do no harm" after all.
Whilst its funny to mock the healing-crystal-brigade, there are alternative therapies being "prescribed" right now that can rot the flesh, induce blindness and kill babies (no, really).
From the unproven to the ineffective to the downright deadly, it's never just a bit of harmless fun when you're messing with people's health.