As somebody relatively freshly out of high school, I would like to pitch in that until current drug education in middle thru high school is changed to be more realistic, plenty of people will believe this as a matter of fact.
If I remember, I did about similar things on the topic of LSD from elementary school, but thankfully by high school I knew there was some degree of ignorance about when the school cop got to say such to us.
And realistically, people of all ages are scrolling across erowid, BL (!!!), and pillreports. Where there is a computer and curiosity, it happens. Thankfully BL tries to follow harm reduction and I would vouch for myths like this being discussed.