I greatly dislike the conflation of things like jailbait (which is mostly provocative clothed images taken voluntarily by teens) and classic child pornography where a 6 year old is brutally raped.
One is harmless the other involves lifelong trauma.
It's not necessarily harmless. JB includes nasty creepshots. And even if the subject took the photo themselves, it's unlikely they wanted a bunch of weirdos on the internet to lust over it. And if they somehow did want that lust, it's even more unlikely that they fully understood the consequences.
All of that can end up being very harmful to one's mental health. And that's not even accounting for the people who try to physically go after those children after seeing them and convincing themselves that they "love" the child.
That subreddit was exploiting children for sexual gratification. It wasn't just teens, and it wasn't people posting purposefully provocative images. It was children living their normal lives and having their pictures exploited for the sexual gratification of perverts.
One is harmless the other involves lifelong trauma.