There seem to be a couple of implicit arguments in this that I find interesting. First, that others aren't to be trusted. Second, that software is in no way an invention.
Regarding the first, I think that for most people they have to rely on the developer of the software they use. If the developer decides to stop working on it they can get screwed. With open source software they may be able to find another developer, but then they are simply at the mercy of the other developer. Their lack of freedom isn't shaped by whether the software is open source or not, it's shaped by their lack of knowledge.
Regarding the second, it seems that the argument for free software is an argument for free speech. This in essence means that software is exlusively a work of creativity (an thus copyrightable) and is not a work of invention (thus not patentable). I don't completely buy this argument. I think software is unique in that it has aspects of both creativity and invention. On one end of the spectrum _why would definitely epitomize the creative aspect of software. On the other end, software paired with super computers and embedded systems certainly come closer to machines.
Overall, I these are tricky things to deal with. I don't think that all software should be out in the open, nor do I think that every piece of software should be cloesd away. I think the free software community needs to have a more nuanced view of the world and that having one will bear more fruit.