This is another huge problem with RMS: the nitpicky obsession with language. Although, in fairness, this seems to be an issue with a lot of technically-minded people. Words are not like code; a word can be imperfect but work well enough in context. Code isn't like this, of course. Even if it's obvious from context that you're writing a conditional, using "=" instead of "==" won't work. But language isn't like that; "close enough" can be just fine, and over time, meanings can evolve.

"Open-source" is a term that a lot of people know and use. It's fine. It's not perfect, and its meaning does not perfectly encompass everything that FSF stands for. Who cares. It's good enough. These arcane, pedantic debates about "libre" (not an English word) versus "FOSS" (an acronym that must be learned) versus "free" (a word with a confusing valence of connotative meanings) are off-putting and distracting.

A lot of activists get distracted by this kind of nerd-bait. Somehow, smart people get convinced that if only we can get people using the right words "I call them used not users" then we'll win the argument via some linguistic cheat code or something. It just doesn't work like that. Here's a good discussion of how climate activists can't get out of their own way on natural gas terminology and some evidence for why the entire debate is pointless: https://strongmessagehere.substack.com/p/words-arent-magic