It’s been just three short years since cannabis was legalized in Canada, but it’s already clear the nation’s exorbitant taxation on cannabis cultivators is not only unsustainable; it’s killing craft growers that are paying more in tax than they earn in margins. Earlier this month, Tantalus Labs CEO Dan Sutton outlined exactly how problematic Canada’s cannabis excise tax is, with small businesses paying as much as 30 percent of their top line revenues to it,…