Honestly, I’m sick of adults treating kids like they don’t understand how fiction and adult content work.
Give kids credit. They're not stupid - half of them are highly intelligent little tech wizards that could probably weave a social-media net more complex than your grandmother’s lace doilies. They are more than aware that fiction isn't real. They know acutely that life isn't a movie or a book or a fanfic that starts 'and they were roommates'. Most minors in fandom are fully aware that the a majority of the material they’re interacting does not, in fact, involve real people’s stories or names or likenesses. If you’re going to interact with them, at least grant them that acknowledgement.
What kids do tend to have trouble with is identifying nuance. A lot of the time, this is because many of them haven’t had high-level lessons on nuance and literary techniques - they’ve gotten into basics, but any adult with a degree in literature is going to have a much broader grasp of how written (drawn/produced-somehow) content works. However, because heavily nuanced content is often more complex and often less black-and-white morally, this means that heavier topics often need to be looked at through a more mature lens for the nuance (or lack thereof - terrible stuff does exist on the internet) to be fully understood.
For this reason, a lot of darkfic/all nsfw/related topics should be and are rightfully considered to be adult content, and adults should never actively seek to introduce this content to a minor. Adults who make adult content should actively encourage minors to stay away, and shouldn’t discuss those kinds of topics with minors. If a minor has a burning desire to understand adult content at all costs, they should be redirected to an age-appropriate resource from professional sources - not given explanations from a Tumblr stranger.
HOWEVER, at a certain point, it is an individual's responsibility to manage their own experience online.
If something is properly identified as adult content (which it should always be) then it is an individual’s job to avoid that content if they are uncomfortable with it. For the most part, if a book/fanfic/fanart/artwork is properly tagged with warnings, kids are in fact intelligent enough to know better than to read or look at something they shouldn’t be reading or looking at. Will some kids look at it anyways? Well, unfortunately so. There’s no way to create a publically accessible space for adults without allowing people to lie about their ages and pretend to be older so they can view adult content. However - this does not instantly mean that adults are responsible for the actions of kids. If a teenager voluntarily clicks into a work that has been advertised as adult content, then they have made a conscious decision to view that work.
And, because we are acknowledging that kids are old and intelligent enough to understand fiction in general, because we are acknowledging that being a minor doesn’t invalidate well-constructed arguments, we also must extend this acknowledgement to the concept that kids are responsible for their own decisions when they choose to look at a work that is tagged for adult content. Being a minor does not take away a person’s agency and ability to control their own behavior. Being a minor does not automatically lessen a person’s ability to construct and defend an argument or opinion. But it also does not lessen their culpability when they do something wrong or cruel.
Adults posting properly tagged content (improperly tagged content is a whole different can of worms) are putting out warning signs for kids to stay away. They’re putting out warning signs for adults uncomfortable with the topics discussed to stay away. They are purposefully discouraging individuals uncomfortable with the subject material to avoid their work, but also inviting critique and feedback from individuals who want to evaluate the nuance of the work they’ve created and are comfortable seeing the fictional content in question. However, banning or restricting the kinds of adult content that can be produced on adult-oriented sites (not including illegal nsfw and content exploitative of real individuals) because a kid has chosen to access said content in spite of warnings, ignores the fact that minors are capable of critical thought and have a degree of agency that makes them responsible for their own behavior.
TL;DR - It is the responsibility of an adult to guide and encourage kids to stay away from adult content via use of proper tags. It is the responsibility of a minor to take that advice and stay away from works marked for adults, especially if they are uncomfortable with the material. It is responsibility of the individual to cultivate their fandom experience. It is the responsibility of the community to provide tools for people to cultivate their fandom spaces.
Note: This discussion does not include untagged adult works. In these scenarios, the poster of the work in question is indeed responsible for others mistakenly viewing their piece
