Because no one counts Android as a Linux distro, and they shouldn't. They couldn't be more oil and water from the rest of the Linux ecosystem. The term would instantly become meaningless. When people talk about alternative to glibc it's meant to be other software that lets you run applications targeting libc.
When the question is "how accurate is it to refer to Linux systems as GNU/Linux", and 3.6 billion devices run Android, and probably as many TVs, home internet devices (modems, wifi, etc), don't ship with the GNU userspace, then the answer very well might be "not accurate at all".
In fact, at this point, I would be surprised to learn that there are more Linux based computers running GNU userspace than not running GNU userspace.
In my house, off the top of my head, I can count 7(!) devices that I know for a fact use Linux and don't have the GNU userspace, three that I'm unsure of, and two that do. And, you probably also have more Linux devices in your household not running GNU userspace, than those that do.
As for the compiler? That's a valid point, but I don't think that earns you naming rights :) We don't call it Windows/Visual Studio 11 or macos/clang.
