A couple of weeks or so back, Mangadex apparently started gradually removing lolicon and shotacon works from the site, particularly explicit ones, to spare themselves from the legal trouble they may potentially get into for hosting them.
However, I guess some non-explicit works have been targeted by the sweep as well and that got the scanlators worried. Either that or they think the incident will be a slippery slope leading into stricter standards over what is and isn't allowed on the site.