GNU gets credit for the GPL, and for being the first major project to start to create a free Unix operating system. So it's true that when the Linux kernel was first released, the fact that you could boot a usable operating system on top of it was due to GNU.

But...the success of what most of us just call "Linux" since then is due to thousands of individuals and organizations other than GNU. The vast majority of free software running on top of a Linux operating system has nothing to do with GNU and is not licensed under the GPL.

Let's say I'm running Linux on a server, for a small app running the MERN stack. Literally none of the MERN stack is GNU.

Let's say I'm running Linux on a desktop. I'm depending on Wayland, KDE, Chromium, VSCodium, and a dozen other tools, none of which are GNU.

However, the fact that I can use the same OS to run a tiny embedded device or a superpowered server, that's due to the Linux kernel and the thousands of individuals, organizations, and companies who have made it into the most efficient and versatile operating system kernel in the world, period.

So to me, I have no problems at all calling the operating system "Linux".