Summary; the Operating System, of which there are many variants known as “Distributions”, is “GNU/Linux”. Some distributions choose to use this term verbatim, like Debian GNU/Linux, and others don’t, but they are all GNU/Linux variants all the same¹. The kernel is named “Linux”, so you can call it “the kernel” or “Linux” interchangeably.
① Except the ones who go out of their way to exorcise the GNU components but still use Linux; one example of a project which does this is Android.
For something to be GNU/Linux, it must use the GNU base system and toolchain - the core/find/inet/binutils, glibc, bash, gcc and so on.
There are generic Linux distributions that also do not. Alpine Linux is one of them, using musl libc and busybox, eschewing GNU software wherever possible. Though, the question arises - is a distribution of Linux always GNU/Linux if it uses GNU software at build time, even if it's almost entirely stripped of it at runtime? That is to say, the use of gcc, GNU make and autotools are largely unavoidable in bootstrapping a Linux platform, or even Unix software in general these days - even if llvm/clang are making progress.
I would say that if a project goes out of its way to eliminate GNU components, it is only fair to refrain from calling it “GNU”. But it isn’t “Linux” either – that’s still the kernel. There is not, in fact, a name for such distributions. Maybe “Anti-GNU” could work, since to remove the GNU components, you would have to have a rather large anti-GNU zeal. These are rather rare, so I guess the need for a special name has been small.
Although, now that I think about it, there probably is a name for this sort of thing, because we do it often, particularly with brands. Marlboro cigarettes. Pepsi soda.
There's always a grammar to language. The fact we might not know it doesn't make it any less real.
though there is a bit of syslinux/grub stuff that isn't strictly this.
The article has since been changed to simply use the name “Linux”, so I could understand that someone could become confused about what callesgg was talking about.