Turning Down Proprietary Software is About Making Society Better
Since some of the latest smears against Software Freedom are instead surrogates (attacking RMS to discredit the ideas) let's examine the idea that preference for Free software is some kind of extremism, as there's also a tendency to say environmentalists are radicals and some people call feminists "nazis". False equivalences and mis-characterisations such as these serve nobody. They merely incite people.
Proprietary software is everywhere, even embedded in a lot of hardware. Many modern gadgets contain in them proprietary designs, based on proprietary schematics, code etc. So to avoid all proprietary software is pretty much impossible; even the 'RMS types' need to use an ATM to get cash or walk into a bank to ask for cash (which would involve tellers using proprietary bank terminals/computer systems). Absolutism is possible only in theory, e.g. living in a cave somewhere without something basic like food or medicine, so think hunter-gatherer lifestyle.
Similarly, environmentalists need some fuel (e.g. for heat and travel) and vegans constantly kill germs inside their bodies; it is inevitable. Even without pesticides, agriculture will involve some deaths of many kinds of insects.
Proprietary software is not going to go away entirely, but curbing its adoption would provide more incentive to make something that's currently proprietary a bit freer (or entirely free/libre) over time. In turn, computer programs can become less oppressive (or be forked to make them so). Similarly "dolphin-safe" labels made some giant corporations more inclined to do or embrace responsible fishing (fishery and drift netting cannot co-exist for long).
When we say "no" to proprietary software we send a message; we encourage peers to reject proprietary software and companies to keep their code visible, honest, more respectful of users, who/which may be customers/clients.
The early(ier) Web was a lot more open. It had pages, not "webapps", and it wasn't hard to learn how pages worked. It was a lot better privacy-wise, it was far less bloated, and exceedingly portable.
The more proprietary things become, the more power we give some already-powerful companies over everybody else.
Software Freedom isn't any more Utopian a vision than women demanding the right to vote. We should not be tempted to shame people for merely trying to keep programmers honest and human rights-respecting. █