Additional info I've been tipped off to that may not be included in any of the linked threads: before becoming an admin, the person in question moderated subreddits specifically for teenaged audiences. I cannot link to proof of this because it uses their full name which reddit won't allow me to say, but it's from a well-known and reliable online newspaper.
Yet more info that I've been shown screenshots proving (out of respect for the person who showed me I cannot share them, unfortunately): as part of their duties as a reddit employee, the admin in question has been in charge of reviewing content for potential minor sexualization, and has explicitly refused to take down content containing sexualization of children. She then threatened to ban the user submitting the reports for "report abuse." Why does reddit allow this to happen? Is there literally zero oversight here?