I think it's best not to conflate issues -- i.e., yes, those who acted irresponsibly by perpetrating fraud should be penalized.
Those who need cannabis for medical reasons should be allowed to.
I agree that excess of sugar and immoderate use of other substances is harmful.
And Michael Phelps violated laws, he was smoking pot, and if companies no longer want to use him as a spokesperson because by his actions he tarnished his heroic image, then fine.
But it's also true that pot is not benign. Count me as someone who has inhaled. However I recognized the dangers and quit when I was 19. My first husband became a pot addict, and still is. His personality became altered. He lives in a fantasy world. He's not the only person I know like this. Maybe not exactly refer madness, but these lives were destroyed, and their lives touch other lives, like my children's, so it's not that they're hurting no one else. They are.
We once lived in an area in California surrounded by pot growers. They were dangerous people who had amassed a great deal of firepower, and even were reputed to have buried mines on their property.
Here's a link to a report about a UN position about the dangers of marijuana. I don't think that everyone involved in these positions are also going out and drinking until they pass out every night.http://rawstory.com/news/2008/Dangers_of_cannabis_must_not_be_0219.html