Then you could argue that any embedded device that runs the Linux kernel is not Linux because it doesn't use the GNU userland. I think its splitting hairs, anything that runs the Linux kernel is by definition, Linux. You can replace the GNU userland with anything you want, it doesn't suddenly make it a completely new operating system.
Sounds like the argument is a question of definitions - does "operating system" mean kernel, userland, or both? You argue that changing the userland doesn't change the OS. I could counterargue that Debian/kFreeBSD is the "same operating system" with a different kernel.
RMS believes that userland makes an OS, because he wrote a userland. Linus believes that kernel makes an OS, because he wrote a kernel. Calling Android "Linux" is like calling Windows 8 "Windows NT", i.e. correct if you're talking about kernels and wrong otherwise.
