Here's one point I want to stress.
There were concerns that this incident may tarnish the western Touhou community's reputation. Here, I echo N-Forza:
I wouldn't be too worried about that, provided a second similar case doesn't crop up (and it better not). There are already a number of foreigners who are creating under ZUN's guidelines, so it would take a little bit more before that trust is totally lost.
A Japanese Touhou doujin game developer also told me as much
on Twitter.
In particular, this is not a good reason to get into a heated argument.
Some data to reassure you: I've been following every tweet search result for
東方 大乱闘,
東方 スマブラ, and
東方 WiiU from the beginning (and also threads on 東方裏, etc.). There were never all that many relevant tweets besides those linking those articles. There were a good number of tweets on the 15th about the correction regarding WiiU, but after that the number dropped to fewer than 20/day. Information about the game never even spread that far. (I even saw a tweet that seemed to think that the whole game, not just the WiiU part, was false information, but I can't find it now.) The handful of users from Japan who continued to follow the information were also reading this discussion on MotK and understand that the western Touhou community disapproves as much of FSS's actions.