Could you elaborate on how it is difficult to deconsor? Is it just that it's hard to find?
Bishop (the original Japanese publisher) owns the uncensored materials. Because of Japanese laws all hentai and porn is required to be censored (so they have to include those annoying pixels/mosaics) If another country such as America licenses the game (pays to release it legally) then the uncensored version MAY be handed over.
Most English companies won't bother getting a game if they can't get the uncensored version unless it's very popular. Japan may resist giving out the uncensored version even for a pile of money because then fans in their own market (Japan) would be tempted to download or reverse import the uncensored version. Why pay for their own localized censored version if another country has a less expensive and better version available?
This game's English translation isn't official. It was by a fan, Dekiru Translations.
Meaning he obviously did not pay Bishop to own the game; simply worked on the censored Japanese version (the only copy available)
Fan translations for censored versions are better than nothing but once they're out there, there's less incentive for a company like MangaGamer to pay for the game (uncensored) and release it themselves since it's harder to sell a game that's already been available for free.