Why are there so many myths in circulation about weed?

A lot of the anti-drug folks seem to have these misguided, wacky beliefs about the drug, for example, that it kills brain cells in the same way alcohol does or causes cancer in the same way cigarettes do. There's also the one about causing laziness, but any reasonable individual should be able to conclude that ociation does not imply causation. Have you considered the possibility that the people that enjoy weed may in fact just be lazy people? And of course there's the ridiculous notion that it is addictive or a gateway drug? Christ, chocolate is far more addictive than weed. I've never known anyone not able to quit smoking weed for any length of time. What is it that keeps these silly ideas floating out there? I know they exist because I come across people clinging to these illogical umptions all the time. I'm not asking why it's not legal which it of course should be. I know the answer to that, just ask the tobacco, alcohol, oil, clothing, and agricultural lobbies.