As for you final claim, sure, competition is always good and a libertarian is never going to argue that local food or local farmer's markets should be banned. The issue with locavores is that they are making the moral and, eventually, the legal case for locally grown food. The libertarian and other critic of local food is arguing that local food is not a realistic goal and would impede choice in what a person could buy.

If you want to shop at a local market and pay higher prices for less selection, then by all means do it. Just don't punish other people who don't want that.

Economic arguments by locovores are often misguided, but those aren't the most important arguments. Other things being equal, I like knowing the farmers who grow my vegetables — it gives me a better sense of how long it's been since the produce was picked, the conditions of production, etc. I also feel better about knowing about the conditions of factories where my computers are made and my shirts are sewn, because moral preferences help drive my economic choices. This preference is particularly prevalent when it comes to health issues. People want to know that kids toys are safe. Or when it comes to health, while I'm pretty indifferent as to whether my mangos come from Haiti, Taiwan, India, or Indonesia, there are certain products (unpasteurized cheese is an example) that I'd pretty much only eat if I know exactly who's making it.

In my neighborhood, the most visible manifestation of the movement is a series of small, weekly markets. That means more and better choices and increased competition — surely you can get behind that.