Linux is not a operative system and calling it that was just a temporarly quirk, based on the concept that a operative system only has a single available kernel.

In Debian, the Linux kernel is just one of many optional packages. Replace it with BSD and you still have Debian the operative system, running on a BSD kernel.

Some people call it a Linux distribution, but that's incorrect. Its a Software distribution, similar to how Apple distribute software through the app store, and how Microsoft distribute software through the windows store. To link the kernel to the distribution make sense if the distribution only support a single kernel, but that's not true any more. Debian is no more a Linux operative system than its a BSD operative system or a Hurd operative system. Debian is however a operative system.

If there is one thing I wish people would do it is to stop confusing the role of a kernel and the role of a operative system. I don't go to the kernel.org and expect to get a full blown operative system to install on my laptop. I don't tell people to go there when suggestion an alternative to windows and mac. Nothing that people use to distinguish which operative system they currently got involves a kernel, and one do not talk about kernel code when recommending people to switching from one operative system to an other.