There are likely a few reasons.
1) Dev refused to cooperate with steam moderators. Moderators asked her multiple times to not rampantly delete/edit out what she called personal attacks, because that made them incapable of actually doing something about the action. Steam got fed up and said forget off and pulled it
2) Dev abused her moderator power in the discussion board by consistently locking/deleting threads and posts criticizing the game, steam said forget off and pulled it
3) Low quality of content (forgetin doubt it though) so either party pulled it
4) Probably the most likely reason, Wu was alledgedly promising game keys to people who le upboated the game. Valve took an official stance on this yesterday.
http://www.eurogamer.net/articles/2015-02-11-valve-devs-should-stop-gifting-game-keys-to-win-steam-greenlight-votes5) Also the most likely reason, bot abuse to vote the game in. There is a lot of evidence of bots being used to upvote the game with throwaway steam accounts.
6)
https://twitter.com/PhoenixCE/status/563680697525624832/photo/17) There's evidence that she fudged the numbers on metacritic too. All of the positive (7+ rating) reviews are made by accounts which have only ever reviewed one game - Revolution 60.
8) It's entirely possible that valve wasn't thrilled with the amount of controversy being generated by the title and told Wu to forget off just for that but I doubt that as well, after GabeN pulled executive orders out on Hatred.
forget!!!
[ig]https://pbs.twimg.com/media/B9mFABbIEAA9xJM.jpg:large[/img]
HEH
forget