If mj were to be fully legalised as a medicine then drug companies would lose a fortune and sack people, the stems and branches would be turned into hemp fibres which would cost jobs in the wood-chip, cotton and nylon industries and the leaves could be used to make hash or canna butter/oil for cooking and baking products to be sold in cannabis clubs. Cannabis can actually generate quite a bit of money in the local community, money the federal government can't tax as mj is not a legal drug under their laws.

As to why the DEA is targeting marijuana and not the heavy drugs out there, crystal meth is cooked up in a day, a quick grow from seedling or clone takes 3 months plus, cannabis growers are easier targets than meth cooks. As for the cannabis clubs, they're just sitting there so the DEA can hit them when they feel the climate is ripe to ask for higher budgets to meet the increasing costs of the war on drugs.

I'm glad the Australian government is not quite as harsh on us as the US gov is on its own citizens, the Australian federal government cannot over-rule the state governments on illicit drug usage and manufacture laws, it's a pity that none of them have the balls to be the first one to at least make mj available to med users.