You may disagree with me of course, but this kind of understanding of OSS is very very common. Most people, even software developers do not even know there is a difference between free and open source software. And as I have suggested before in another comment: Consciously check the licenses of the next 10-20 repos (or more, if you have time or motivation), which are labeled "open source" and you will very quickly see what many people think open source license to mean. I'd love for it to not be so, surely. I would like to discover, that I have, mostly dealt with a niche group of software developers, and that the broad majority in fact knows the differences. I have a hunch though, that this is not the case, as I always check the licenses of repos and almost always see MIT or BSD when its label is "open source". This is my experience on an almost daily basis on the job, but if you have good sources, please link them to me, to prove me wrong about this.

As for the second part: Time for first hand source: https://www.gnu.org/philosophy/open-source-misses-the-point....

(quote start)

"“Free software.” “Open source.” If it's the same software (or nearly so), does it matter which name you use? Yes, because different words convey different ideas. While a free program by any other name would give you the same freedom today, establishing freedom in a lasting way depends above all on teaching people to value freedom. If you want to help do this, it is essential to speak of “free software.”

We in the free software movement don't think of the open source camp as an enemy; the enemy is proprietary (nonfree) software. But we want people to know we stand for freedom, so we do not accept being mislabeled as open source supporters. What we advocate is not “open source,” and what we oppose is not “closed source”. To make this clear, we avoid using those terms."

(quote end)

People intentionally making free software do not see themselves as merely open source software making. They do not wish to be mislabeled. Is that not enough for you? I mean, what more do you need, for me to convince you, that this subset-superset-structure, you are proposing, is not according to the definition of what free software is?

Now I don't know in what circles you work, but I suggest, that the people take another look at the definitions and begin distinguishing, if they have any interest in using the correct terms. Why is that important? Well, another quote from the same page:

(quote start)

Some of the supporters of open source considered the term a “marketing campaign for free software,” which would appeal to business executives by highlighting the software's practical benefits, while not raising issues of right and wrong that they might not like to hear. Other supporters flatly rejected the free software movement's ethical and social values. Whichever their views, when campaigning for open source, they neither cited nor advocated those values. The term “open source” quickly became associated with ideas and arguments based only on practical values, such as making or having powerful, reliable software. Most of the supporters of open source have come to it since then, and they make the same association. Most discussion of “open source” pays no attention to right and wrong, only to popularity and success; here's a typical example. A minority of supporters of open source do nowadays say freedom is part of the issue, but they are not very visible among the many that don't.

(quote end)

Thank you for now engaging in an actual discussion about the subject and bringing arguments.

"check the licenses of the next 10-20 repos (or more, if you have time or motivation), which are labeled "open source" and you will very quickly see what many people think open source license to mean."

That proves no such thing.

You might as well say "check the programming language used on the next 10 or 20 repositories and you will very quickly see what many people think open source programming language to mean."

I only ever licence my own stuff as gpl or the closest cc analog for projects with a physical component, and in almost all conversations, with people in and out of any IT related field or hobby, I call it all open source.

The special meanings for "open source" and "free" are definitions a very few people have come up with as a way to give a label to a distinction which exists so that they can deal with that distinction, but no one I know ever uses those terms in that way in any ordinary conversation or even writings. Even professional writers writing news articls, most frequently use the term open source to apply to anything that isn't closed source. Even they might only say "free" to mean without monetary cost.

The special definitions are almost like a document-local definition. They aren't even jargon. Meaning, you can't even say that everyone in a given field means those definitions when they say those words. The set for which that assumption would be true or at least plausible is only everyone in one or two organizations.