the only people that I know that call it a scam are the people that expect to get rich while sitting around. I've got friends making thousands a month doing this, you have to put in a little work, your not gonna get rich without doing a little work.
There is no way that homeless people are selling Vemma unless they have no idea what they are doing. Vemma is not a MLM like Amway. you do not sell product, you simply get others to signup under you and use the product. I spend about the same amount a month as I normally would for energy drinks, and make money off of it.