See, as much as it's a meme at this point, this is really where the GNU/Linux distinction is important. WSL is really GNU/Windows which is probably horrifying and a massive success story for the FSF.
Can you clarify the GNU/Linux distinction with regard to the WSL? I mean... isn't the main WSL layer a flavor of Ubuntu?
Linux is the name of the kernel. It is also used as the name of the kernel plus the userland, which has a lot of GNU code in it (although give Poettering some time and we'll see). WSL is the userland without the kernel.
WSL is running Ubuntu software with the GNU userspace on top of the Windows kernel using a Linux translation layer.