Very well put. I'm not a libertarian myself, but this is certainly quite thought provoking, and at the moment correct. I do worry about mercenary or private security companies, which can be made to function like a private military force. It bothers me somewhat that the clients of these corporations are also corporations, so the effect of individuals is a step removed (I have to stop buying things from any company that does business with the security company, making it harder to get information and harder for me to boycott, as it may mean significantly altering my lifestyle).

I also tend to think of "force" as including not only direct physical force, but also coercive forces like deceit, censorship, manipulation, withholding information. The government, of course, does all of these things, but herein corporations are just as bad.