I think it is just as likely to be a libertarian person who finds their legal pursuit of farmers who have (frequently accidentally) had their crops cross pollinate with Monsanto patented breeds to be ethically distasteful.
This is mostly a myth. All of the lawsuits have been about people who have intentionally used Monsanto breeds (mostly just one court case about one farmer in particular). The rest of their lawsuits, which are a relatively small number, have been against people who broke their contracts with Monsanto, not people who have experienced accidental cross pollination. There are no cases of Monsanto going after farmers for inadvertent contamination and the company has even explicitly stated that it will not sue farmers for it.
Also, while its hard to pin down libertarianism, there is a lot of conflation between libertarianism and anarchism online. There is nothing un-libertarian about what Monsanto does. Classic libertarians believe in property rights and contractual rights. Monsanto's legal actions largely rely on a web of contracts. There is nothing about classic libertarianism that is inconsistent with patents as property rights. Indeed, patents are a basically libertarian response to the neoclassical economic problem of free riding. The libertarian preference for addressing market failures is the creation of property rights. In this context, its more consistent with classical libertarianism for Monsanto to get property rights in its Round Up Ready seeds, and thus make the money that bankrolls their billions of dollars in annual research, than for say the government to spend that money to do basic research.
Herbicide, not pesticide.
http://www.alternet.org/civil-liberties/noam-chomsky-kind-an...
"Chomsky: Well what’s called libertarian in the United States, which is a special U. S. phenomenon, it doesn’t really exist anywhere else — a little bit in England — permits a very high level of authority and domination but in the hands of private power: so private power should be unleashed to do whatever it likes."
Powerful patents being used to dominate individuals, whether through infringement suits or through depriving them access to the market is about as far from libertarianism as you can get. This becomes more intuitive when you observe that the individual farmer has been put in a "damned if you do, damned if you don't" scenario. He does not, in fact, have his economic liberty.
Your characterization of the farmers plight isn't accurate. They are not in a "damned if they don't" position. The roundup ready plants behave like ordinary plants if you don't use roundup. They had no reason to either enter into contracts with Monsanto or to use Monsanto's property by applying roundup, other than to gain the benefit of Monsanto's invention. Once they do those things, libertarianism says that Monsanto can dictate whatever terms it wants, and furthermore that one of the few legitimate purposes of even a limited government is providing courts for the enforcement of contractual and property rights.
http://leiterreports.typepad.com/blog/2009/08/chomsky-on-lib...
"The term "libertarian" has an idiosyncratic usage in the US and Canada, reflecting, I suppose, the unusual power of business in these societies. In the European tradition, "libertarian socialism" ("socialisme libertaire") was the anti-state branch of the socialist movement: anarchism (in the European, not the US sense).
I use the term in the traditional sense, not the US sense."
The farmer is indeed damned if he doesn't. Monsanto crushes him because he can't compete in the market. Did you not hear of the mass suicides among farmers in India, where they took 95% of the seed market?
Monstanto has been very successful in executing the equivalent of "Embrace, Extend, Extinguish" in the seed market, and now enjoy an 80% - 90% monopoly on seeds depending on the crop. It's now difficult to purchase non-patent-encumbered seeds even if you want to, and if you do so, you're at a severe disadvantage.
Seeds. Think about that for a moment. That small piece of biomatter, the source of life, which grows into staple crops for feeding our planet. This and all future generations of it are patent encumbered, and controlled by a large corporation. To equate this with liberty is hilarious. Laissez-faire capitalism leads only to tyranny, not liberty. Even Greenspan finally figured this out. Too bad it took destroying nearly half of the global wealth for him to do so.
> The farmer is indeed damned if he doesn't. Monsanto crushes him because he can't compete in the market.
So what? That's how the market works.
> It's now difficult to purchase non-patent-encumbered seeds even if you want to, and if you do so, you're at a severe disadvantage.
They're at a disadvantage because Monsanto's product is dramatically superior. Within the framework of libertarianism (American libertarianism if you want to quibble about that), there is nothing wrong with a superior competitor crushing inferior competition.
http://en.wikipedia.org/wiki/Monsanto_Canada_Inc._v._Schmeis...
http://www.truth-out.org/news/item/16985-life-in-the-rural-p...
EDIT: The truth hurts, bitches.