Whenever I've seen it about adults, it's just shipwars, or leftover debris from shipwars. Like in the Sherlock BBC fandom where a loud contingent argued that having the wrong character (of two 30-40 something men) topping was "pedophilia" because one of them was "child-coded". I mostly feel sorry for the teenagers being told that having totally age-appropriate sexual interests (like a 15-year-old interested in a 15-year-old) is pedophilic and they should be ashamed.