Reddit previously allowed essentially anything that was not either illegal to post or breaking the site by organizing vote manipulation and the like. After getting negative press for subreddits that allowed sexualized (but probably not technically pornographic) images of kids, they banned that kind of content.

Reddit positioned itself as a neutral platform with as few sitewide rules as it could have prior to that, and many didn’t like what the change signaled even if they found /r/jailbait disgusting.