What was the reason this question was removed from the front page so quickly after getting so many upvotes and comments?

https://news.ycombinator.com/item?id=7826258

I know the guidelines ask that such questions be sent to hn@ycombinator.com, but I think that's a bad policy to apply universally, as in this case.

When a legitimate question like the above gains so many upvotes and responses, moderators should publicly state the reason for removing it. It's in the mod's favor to do so iff they have a legitimate reason for doing so, as it helps the community understand what mistakes to avoid.