This is not about Bash or any GNU software per se. Bash is just an example of a Linux executable that can be run on this system. One can apt-get install many more Ubuntu application binaries.
Please invest some time to understand what it's about technically.
I do understand that technically speaking, this is an implementation of Linux-compatible APIs/ABIs on Windows, so an ELF binary targetting POSIX-compatible environment could be ran on Windows. No dependencies on GNU OS parts here, of course.
However, please notice that it's also marketed as - quoting the article - "the ability to run native Bash and GNU/Linux command-line tools [on Windows]" and currently implemented as GNU-based OS (Ubuntu) running on Windows. So - in practice - essentially, it's MS-supported (although hosted by Canonical) GNU on Windows.
> So - in practice - essentially, it's MS-supported (although hosted by Canonical) GNU on Windows.
I don't care how it's marketed.
Let me remind you that there have been numerous ports of GNU tools for the Windows operating system in the past. This does not allow you to run any more GNU tools on Windows than you previously had.
Therefore, essentially, this is not about "GNU on Windows". This is about running "Ubuntu Linux software on Windows" including, of course, and in addition to numerous other tools, the GNU tools.
Also, the original statement was: "That is just GNU running on the Windows kernel." This is obviously not just that.
Please invest some time to understand what it's about technically.