Yes, marijuana dispensaries are fronts for criminal profiteers, because they are a place where those who want to sell drugs or engage in other criminal behaviors can find other people who are willing participants. Those who are criminals often know each other. A marijuana dispensaries is more or less a phone book of people comfortable breaking the law.
Marijuana is legal so everyone needs to stop trying to sue the state of colorado they have no idea what they are talking about. It is a legal store that has passed many local government inspections and has obtained all the necessary licensees. If there were illegal activity going on the store would be raided and shut down as few have in the past.
The great thing about marijuana dispensaries is the fact that they are now legal in the select states that they exist in. This means that the need to have a front for criminal activity has been reduced because marijuana is now legal. While some criminals prefer other markets, many who supplied marijuana are only interested in that one drug.