I spotted one of those “Linux, the operating system” inaccuracies and wrote a friendly mail to Jeff Elkner, the author of http://openbookproject.net//thinkCSpy/. Here’s what he replied:

Thanks, Michael!  I've changed "Linux is an operating system" to
"Linux is an operating system kernel" and changed "thousands" to
"millions".

I decided against the appositive you suggested at the end, since it
would require more explaination (what is the GNU system?) and make the
paragraph more difficult to understand.  I'll be sure to look for
other opportunities (particularly in the new preface) to promote
software freedom.

Thanks again!

jeff elkner

Great to see such prompt and positive resonance!

Now it’s YOUR turn to convince kernel.org (as an example) to use less confusing terminology! 🙂