>In that it claims certain things are "common misconceptions"
> while the text is formulated in such a way as it might
> create a new misconception about Open Source vvs. Free
> Software (That Free Software is not also Open Source??).
>[...]
> Libre software is Open Source by necessity. If it
> were not Open Source, then it could not be free.

Open Source and Free Software are too approach of releasing software that result in same thing. Still, these are two different things. You cannot on one side claim that Open Source is made technically better than proprietary software because the source code is available and on the other side claim that Free Software is better than proprietary software just because of freedom.
The two assertions does not get along ; you'll find many case where Free Software is better only because of freedom, but not technically.

So Open Source and Free Software are not really the same thing, because they do not refers to the same thing. However, they share common goal and the license model is most of the time the same ; for that reasons they are tightly linked. But I do not think it is a mistake to say these are different things.

> "and avoid confusing use of terms/nomenclature.
> For example, in referring to the Linux Kernel, and the
> large number of operating system distributions based on GNU/Linux: >don't call everything "Linux", be specific.

That's one way to say things. In fact, this way is more clear than ours, I agree, but it looks more like a recipe instead of a general principle. If fact, what you say is the result of what we say: since GNU/Linux and Linux are not the same thing, referring to one or another should be done with specific terms.

> We're talking about names, not misconceptions...
> common misconceptions are like: "strncpy guarantees
> NUL-termination of the target" (it does not),
>
> or "Windows XP SP1 is more secure than windows '98",
> etc.

Names are supposed to express something. Using unappropriate names reveal misconceptions most of the time.

> There's no Operating System/distribution called "GNU/Linux" either,

There is indeed an Operating System composed of the GNU/Linux and the Linux kernel -- that's what distributions ships, whatever their name.

> Since nomenclature is by convention, it's not necessarily
> misconception when people refer to the "Linux OS", either (sigh)...

Not necessarily. However it is indeed spreading misconceptions to call GNU/Linux Linux. It just leads people that are not aware of the role of Linux in GNU/Linux to misrepresent its role.

> at which point your best option is to task them what they meant
> precisely whenever they said "Linux OS" "Kernel" or "Distribution"

I am not sure to understand what you meant here. However, it cant think of something easier to say GNU/Linux, Linux, or RedHat Linux when you want to name the OS, the Kernel, or a distribution of GNU/Linux.