They are not operating fraudulently. Their customers are buying and getting marijuana. Their investors surely know the risks as well.

If we're looking for an analogy in this space, I think it's more like snake oil. So imagine a company started selling a new "nutritional supplement" or "herbal blend" that helped with anxiety. But it turned out the secret ingredient was weed. That would be a fraud on investors and they could well get charged for that on top of the base drug charges.