The target audiences of open-source vs. proprietary software

I worked for a few months as a developer at a mobile security startup working on encrypted text messaging (in order to prevent this from showing up in searches about them, I won't name the company).  It was a good learning experience, and I generally enjoyed the work.  However, the target audiences (as shown on their blog and in public presentations) seem to be a) people who sext and want to keep it secret and b) healthcare professionals wanting to avoid HIPAA lawsuits.
I also follow the development progress of the Guardian Project, an open-source collaboration to create secure mobile applications (in order to avoid running afoul of my various contractual obligations, I don't contribute to the codebase).  They posted an interesting piece in April about their targeted users, such as nascent social movements attempting to organize, diffuse organizations in oppressive countries, and journalists needing to avoid monitoring in foreign locations.  There's also been talk on the mailing list about the need for secure mobile communication applications among activists, human rights workers, and journalists in Cambodia (the talk was of Cambodia because of a specific case of an activist being killed by military police, but the need for secure communications is universal).
Clearly the difference in targeted audience can partially be explained by the need for a business to make money, compared with the more altruistic forces driving a non-profit.  I don't want to make it seem like the start-up is greedy and only focused on money whereas the Guardian Project is only focused on helping the world (I currently work for a massive corporation and not some charitable non-profit, so it'd be highly hypocritical of me to fault others for making the same decision).  Certainly helping doctors is good, and not all random organizations that will use the Guardian Project's software will be engaged in legal activities, but I think it's interesting nonetheless to compare the targeted users of the two groups.