I'm having a hard time understanding why this is so important? Linux is "just" the kernel. Surely everybody knows this? And if they didn't then surely Android and ChromeOS made that distinction clear?
edit: I'm having a hard time coming up with a name which would be correct and Microsofty enough. But I think it would be a oxymoron.
And in the MS case, the argument is the opposite: MS calls it a "MS subsystem for Linux" but there's absolutely no Linux kernel code in it. Just emulation of APIs and the GNU userland.