1. Sapir-Whorf is racist pseudoscience that was never substantiated and was universally rejected from day 1 by everybody but science-illiterate journalists
2. Even if there was substance to it, it's not relevant to this. People have no difficulty understanding what "Free" means when you explain what you mean. Just as in the above sentence you experienced no confusion at all over whether I used "that" in the indicative or grammatical sense.
The issue is: marketing. Any word that has a precise technical meaning will become non-technical as marketers latch onto the word. Because if its technical, precise, and useful... then marketers will "stretch" the meaning of the word beyond its true definition.
In many cases, the word "free" itself is overloaded. Chosen by the "Free Software" movement because of its ambiguity. Free from cost, freedom to use, freedom of choice... etc. etc.
Stallman wants "free" to mean everything he wants it to mean, without any of the meanings otherwise attached to the word. Its an issue of branding and I've never really liked this aspect of the FSF / Stallman's philosophy.
Ultimately, Stallman wants to distinguish between the "Open Source" community with his "Free Software" philosophy. There's plenty of more appropriate words, such as "Copyleft" software, available at his disposal.
Overloading the "Free Software" word and/or branding is part of the strategy. Ambiguity is good. It allows the people who hear the word to imagine the best possibilities, as opposed to focusing on the technical details or legalize.
I've seen this often, but I don't think it's true. How about "liberated"? This implies that restrictions did exist at one point, which is true, as copyright is assigned by default and needs to be explicitly liberated in most places. It also reminds people who forget to assign a license of the importance to do so.
I'm sure there are other single words that would convey the same message.
As you say liberated software implies a removal of restrictions, but I think it implies it was accomplished by force. I think it would be a good term for someone who believes piracy to be a moral imperative, but I don't think it's a good term for expressing the idea of the author willingly sharing their work.
"And the soldiers liberate them, laying mines along their roads." ~Megadeth
Often you need to explain that free as 'free as in free speech', which probably confuses people more.