I remember the NT POSIX subsystem, which was a bit of a joke. It was badly limited and just seemed to be a box ticking exercise to get past some government requirements (disclaimer: I don't actually know if that's true). Whatever the reason, we ended up having to port our POSIX software to NT because customers insisted it was POSIX complient. I did resent MS for the mess we got into.
I do believe MS has changed. They don't seem to be the conniving organisation they once were, but what does WSL bring to Windows?
Perhaps, they are just accepting that there is something inevitable about all that Linux software that is available out there, and Linux developers could now be supporting Windows with no actual effort. After all Apple have saved themselves a load of effort by using Netbsd. However, something makes me wary. Could we be looking at an attempt to replace the Linux kernal on the servers of the world?