Lots to argue with in a Forbes article here that attacks marijuana taxation:
1. “It’s a basic principle of sound tax policy that the code should not pick winners and losers or disproportionately target certain industries or groups of taxpayers.” There’s a grain of truth there, but pushed to this extreme, it leads to taxing whiskey like wheat, and marijuana like milk.
2. “Because marijuana can be purchased as a cigarette, an edible, a liquid, or vapor, all with a wide variety of concentrations, a specific excise tax is untenable.” That’s a complete red herring. No one else suggests taxing weight or potency at the product level. That would be like taxing rum punch like vodka shots. Just as you tax the rum in rum punch, not the punch product, you would tax the marijuana that goes into edibles and so on, not the final product.
3. “There is no reason why the tax code should deny ordinary and necessary business expenses to legitimate businesses established under state law.” Well, you might think advertising and marketing of marijuana might be (a) unwelcome on policy grounds and (b) protected under some reading of free speech. Denying deductions for those expenses might be the best you can do. More here.