Red Hat being Red Hat, "When is it OK to tolerate the use of proprietary software?" and "When is it OK to advocate for the use of proprietary software?" are unsurprisingly regular topics of conversation. These kinds of conversations are unavoidable in running a large multinational organisation founded on the principles of software freedom and open collaboration.
Benjamin Mako Hill's "Free software needs free tools" is a classic piece advocating for the hardline "no proprietary dependencies" stance: https://mako.cc/writing/hill-free_tools.html
In open source communities, the topic now comes up most frequently in relation to "Why can't you just use GitHub, that would be so much more convenient for me..." complaints directed at open source project maintainers by folks that have been co-opted into GitHub's marketing arm by their well-crafted, venture-capital backed, freemium business model. (Which actually has a nice positive externality, in that doing more of your work in the open reduces how much you need to pay GitHub for repo hosting)
This particularly thought stream was prompted by a desire to find a way to convey just how obnoxious the "I'm OK with proprietary tools, so you should be OK with proprietary tools" mindset can be.
I'm personally entirely OK with making the pragmatic argument for "we're compromising here, to further this other goal over there" (such as reducing the load on volunteers in a community context, or improving strategic focus in a business context), but that's different from telling people that their desire to avoid using proprietary software is invalid and not worth taking into account at all.
I'm probably not the first to think of it, but as the stream title suggests, the analogy that occurred to me is with vegetarianism: the default in society is to pursue an omnivorous diet, making selections based on personal preference.
However, some folks will make a principled decision not to eat meat and become vegetarians, while vegans go even further and avoid animal products entirely.
The analogy with free software advocacy then runs as follows:
if a free software advocate is trying to make you prefer to avoid proprietary software, then that's akin to vegetarians and vegans proselytising to folks that eat meat. This can be done gracefully by focusing on "These are the benefits I personally appreciate", and letting people decide for themselves whether or not those benefits matter to them, or we can be obnoxious about it by attacking people for not already being vegetarians/vegans/free software users/free software advocates. The latter might be emotionally satisfying in the near term, but it's not a particularly effective proselytisation tactic (since the most likely outcome is for people to tune out entirely).
conversely, demanding that a free software advocate use proprietary software for the sake of your convenience is akin to telling a vegetarian or vegan that you haven't bothered to provide a non-meat option for them at the dinner you invited them to. It's saying "Your personal principles make my life more complicated, so I'd like you to just abandon them, since that's easier for me".
Copyleft licensing in this analogy becomes a legally enforced way of ensuring that a vegan recipe can only be used in the preparation of further vegan or vegetarian recipes.
Many folks are fine with that, but some complain:
For folks tempted to say "but using proprietary software is more socially destructive then eating meat", there's a solid case to be made that meat products make a non-trivial contribution to humanity's global environmental footprint: https://en.wikipedia.org/wiki/Environmental_impact_of_meat_production