I imagine a number of situations:
* Suppose I'm unemployed and dedicated to only using free software - I'm offered a job where I'll have to use Windows and Microsoft Word. If I refuse the job because of software freedom. Can I still be claim unemployment benefit?
* I'm an unemployed programmer and get offered at job where I have to *write* proprietary software - I refuse because I won't participate in taking users' freedom. Can I still be claim unemployment benefit?
* I want to park my car in the city, but it's only possible to pay by downloading one of two proprietary apps (real-world situation in Copenhagen) on my smartphone. Can I refuse to pay an eventual fine on the grounds that I couldn't pay?
... etc.
I think the ideal must be for the lack of software freedom to *always* be accepted as a valid reason to refuse a given piece of software, but pragmatically, it may not always be possible (especially, many people like to have jobs and may prioritize that above not using/writing proprietry software).