Steam has made changes to what developers and publishers are allowed to release on its platform to appease payment processors. The purge has also already begun with overt pornographic games being culled from the platform.
Game*Spark (via Automaton) spotted on SteamDB changes were made to the platform’s acceptable games to include a stipulation surrounding payment processors. It does specifically state “certain kinds” of AO games, likely more skewing towards just straight up porn or in the cases spotted, games that involve taboo topics such as incest or slavery.
15. Content that may violate the rules and standards set forth by Steam’s payment processors and related card networks and banks, or internet network providers. In particular, certain kinds of adult only content.Â
This was bound to come up eventually, payment processors are a bit touchy with certain content, already having started issues with a game and manga seller in Japan over AO material found on the site violating its (often undisclosed) rules.