WSL2 is. The first WSL wasn't though, was it?
https://en.wikipedia.org/wiki/Windows_Subsystem_for_Linux
> allows the use of a Linux environment from within Windows, foregoing the overhead of a virtual machine and being an alternative to dual booting.
WSL2 isn't a Windows subsystem by definition as far as I can tell.
Yes WSL2 as WSL 1 was just an implementation of Linux utilities. WSL 2 is a subsystem on Windows for Linux, it's poorly named but makes sense if you take it as Windows' subsystem for Linux.