It's not "bash" on Windows. You can get dash on Windows, or zsh on windows, or Xorg on Windows. The whole "bash on windows" was more evidence to one of the three problems all programmers have: off by one errors and a less-than-passable naming sense.
Just saying "bash on Windows" opens a host of problems that we shouldn't have, like generic bash problems getting the tag because it's "on Windows", or stuff that is specific to the platform not getting the tag because it has nothing to do with "bash" or people tagging it just because.
The technology, in theory, would allow you to run any Linux binary on Windows, heck, you could just install pacman and manage your system as if it was Arch Linux... at such point, there isn't anything specific to "Ubuntu" on it, just that that's the default image you get. Forcing people that knows better, like the answerers, to follow the "wrong tag", because they know the correct terminology isn't productive in the long run. They are going to look for a Windows Subsystem for Linux tag and that's what we should deliver. Stack Overflow already figured out, Super User didn't need a discussion, they didn't create a bash-on-windows tag and I believe that's what we should follow.
BTW, there are less than 200 questions in the 3 sites combined, and we don't even have 20. Being the odd one out doesn't sit well.