What is the point of spending taxpayer money to subsidize big macs, high fructose corn syrup, and cigarettes?

It's called "Red State Welfare." Most of the farm subsidies in the United States go to large corporate owned farms. These farms use bulk pricing to drive independent farmers under by selling at a price that a small independent can never meet, driving down the price of the crop until the small farmer goes broke, and the large corporate owned farm buys his land and expands. ADM, and Cargill have driven the small farmers under, and they hire powerful lobbyists to make sure that they get the subsidies.