The development team has stated they are working on age-based content gating (https://wiki.vrchat.com/wiki/Content_Gating); however in an interim condition use the systems we have, to avoid people seeing things they don't want to, enable all the sliders as on as a default. Make the individual user choose and elect actively what they want to see.
All players still need to follow the TOS and rules regarding appropriate avatars and activities in public instances and in private instances.
Who do not even seem to be aware such Content Gating is possible. Turn it on as a default, this way everyone can choose actively and consent to what they want to see.