You're making a lot of conjectures and assumptions there. Moreover, we do ask creators who publish adult games to mark them as NSFW. Games marked in this way don't show up in listings except for people who log in and indicate that they want to see them in their account settings. And we don't allow underage people to make accounts, as per current legal regimes in the US and Europe.
Now, if you're logged out or browsing in SFW mode and see a game with inappropriate content listed, please report it and a staff member will look into it. Could be an honest mistake, no need to assume the worst up front.