From Fan History Wiki
In the history of fan fiction, if any one has actually been convicted of this, no one knows or has spoken of it. The community has people from with varied backgrounds, having had different experiences. Some of these are not pleasant. Some members of the community have been rape victims. Others have had various diseases. The community has lost people to these diseases. There are members of the community who use illegal drugs.
But pedophiles, if there are actual pedophiles in the fan fiction community, no one knows. Still, starting in 2001 or so, accusing some one of being a pedophile became the I'm out to screw you accusation of choice. If you wrote a story featuring a minor in some way where sex was involved and you'd crossed the wrong person, pedophile. If you had a lot of teenage aquaintences in fandom and crossed the wrong person, pedophile. This sort of attitude increased various levels of hostility in fandom. This accusation, the one of being a pedophile, was a switch since the accusation of being gay or lesbian and calling an employer and telling them that just no longer was cutting it in terms of getting a person in trouble.