The game platform Steam has an anything-goes policy toward what it publishes. But the resulting kelp mat of smut has spread enough to lead it to institute moderation by the back door: freezing approvals in certain genres while it develops 'filters.' Targeted most clearly are visual novels, manga and erotica. Fans and developers of erotic manga visual novels are most displeased!
Based on just the developers coming forward, it seems like visual novels with some degree of adult content are in the crosshairs of this approval freeze. One such dev shared their recent conversation with a Valve employee, seemingly from Valve's developer portal, and noted that their game was being held despite censoring out adult content and images from the Steam edition ahead of time, a step the dev says has worked for their past releases on Steam.
While Valve has yet to comment on the criteria under which it is selecting games to withhold from Steam for the time being, sudden policy enforcement shifts have slighted visual novel developers in the past. At one point a few months back, Valve reached out to several visual novel developers and threatened to delist their games, all of which had been previously approved for Steam release, unless those devs patch out content deemed inappropriate. However, Valve later backed down from those threats.
There are maybe colder facts in play here than the usual freezepeach discourse. More porn means more chargebacks, which means the payment processors taking an interest in what is being sold and turning the screw on Steam.