Providing POSIX and Linux-specific APIs does actually place them into Linux ecosystem.
Programs bult for Linux suddenly can be run for Windows users. That's a boost in adoption potential for Linux programs (large part of the ecosystem). And adoption is very impotant for further development and success of software.
On the other hand, for Linux users this makes Windows more attractive - why not choose Windows for your next laptop, if all your Linux software runs there. That undermines Linux userbase.
WSL is winning people over who had left Windows simply because the dev experience outside of the VS IDE is sub-par. We'll see what this means for Linux.
It could mean that people start realizing that there's gaps between Windows and Linux that need to be closed to make Linux more attractive to users. Alternatively it could mean that people don't acknowledge those gaps and instead gripe about EEE.
Yeah, that's what gets me: it's obviously engineered to drive traffic one way without giving anything back to the community. I'm sorry, but I'm not interested in APIs to interact with a black box. Until Microsoft makes Windows user-controllable, I will never treat it with respect.
I do see your point, however, and I hadn't thought it of that way; do you see anywhere the community might pick up on this for some benefit?
Many ways. For example, it is more compelling to choose Linux as the target platform for new programs, because that way the program works both on Winoows an Linux. Therefore, more software for Linux world.
Programs bult for Linux suddenly can be run for Windows users. That's a boost in adoption potential for Linux programs (large part of the ecosystem). And adoption is very impotant for further development and success of software.
On the other hand, for Linux users this makes Windows more attractive - why not choose Windows for your next laptop, if all your Linux software runs there. That undermines Linux userbase.
But overall, I feel WSL is good for Linux.