One of the other points Kristof makes is that the high sugar content in soda preps Americans for greater amounts of sugar in their diet. This is convenient, since high fructose corn syrup is in "demand" thanks to the continued subsidies provided by the American government. We can complain about obesity, but there's going to be little effect until we change the fundamental diet of Americans and their easy sugars.
Coming from a state whose main livelihood is agriculture, and particularly corn, it's hard to say that we should ditch the subsidies altogether... The argument, though, is that the subsidies are subverting capitalism and supporting an unhealthy practice (both business and bodily). Maybe it's time that we encourage farmers to take on naturally sustainable practices or find another way of supporting themselves. (The corn that's being subsidized isn't necessary for the good of the American populace, and we won't fail without it.)
I like to think that I'm a socialist at some level, that the government would do good to help less fortunate -- but I don't like the idea of helping so much that people, such as corn farmers, become reliant and take advantage of the support being provided.