Ubuntu on Windows

It's time that people stopped using the term 'Windows' for this operating system. The Free Software Foundation created the bulk of the userspace, under terms that allow anyone to share, modify and fork the programs, and then Microsoft came along with the one last missing piece of the puzzle - the kernel, and completed the full operating system, which, to be frank, users find completely unusable and worthless without the free software provided by GNU.

The kernel is an important part of the system, sure, but only one among many important parts. We therefore think that, to give full credit to the authors, the whole system should be termed GNU/Windows.

I have problems understanding your point here. What was announced was not a new operating system but a translation layer built into Windows 10 that translates Linux system calls to their Windows counterparts.

I also bet many people would disagree with your statement that W10 is unusable and worthless without this feature.

The Windows kernel always existed and has evolved over the years: NT, 2000, XP, Vista, 7, 8, 10. They didn't develop it as the "last missing piece of the puzzle".

It's a joke: https://en.wikipedia.org/wiki/GNU/Linux_naming_controversy