"Free software" and "open source" have very clear meanings in software industry. Nobody can force you to use them correctly but don't get angry or even act surprised when people complain that you are wrong and even deceitful (when the error doesn't seem naive).
If you go to a flight engineer and say that a plane has a high risk of stalling, first thing the engineer thinks would be a problem in the aerodynamics, not some engine problem, which would not make sense according to the dictionary definition: Stalling: Stop running, typically because of an overload on the engine. (Random example from the top of my head and my example can theoretically be very wrong, but I hope my point is clear).
I agree with you on "open source", that term was basically introduced by the OSI and people still stick to the OSI definition, but I cannot agree with you on the term "free", that word has a very long history of meaning gratis long before the FSF.
I personally understand different things when I hear that an application is "free" vs that it is "free software" [1].
It also helps to look at the more correct terms to use when talking about a different kind of "free" [2].
It doesn't actually matter, but even if we dig the actual root of the word, and its usage, we see that the "libre" meaning precedes the "kostenlos" (without monetary cost). It meant "noble, free person" in the proto-Germanic [3]. If you say that someone is a free person, no sane person would think that he/she can be owned for free. So the phrase "free software" is a very unsuitable substitute for "free to redistribute" or "free to use", even when you ignore the industry jargon. License to use it is free, not the software.