> Furthermore, any C++ programmer who says they do not know C, knows neither C nor C++ (hence my preference in using C/C++ as a shorthand to encompass both and highlight the dependency of the latter on the former).

Right, but this dependency is one-way. There is an entire legion of C programmers who reject C++ (most notably Linus), so claiming that almost all C programmers are also C++ programmers is a bit off.

What i meant was that almost all C programmers are aware of and know C++ to varying degrees. But they choose to not use it for their application based on needs/expertise/etc.

Linus Torvalds objection to using C++ is perfectly logical for his use-case. I know many embedded programmers who refuse to use C++ even though they understand and agree with the benefits that it can bring to the table. Their C expertise is so good that when they program, cognitively the language just disappears and they "flow" through the problem solution implementation. This is the crux of problem-solving.