Earlier quoted context omitted.
I think it is more significant from a user's perspective that they get the GNU tools to run on their NT machine with MS support. What's the use of Linux syscall -> NT syscall translation if not compatibility with developer tools, most of which are GNU software?
> developer tools, most of which are GNU software? such as python, nodejs, elixir and PHP?
EDIT: Yes, there are non-GNU Linux distributions, but WSL is based off Ubuntu specifically and ships with a GNU userland by default.