I remember that period as the one where non-nude sexual images of children was a huge problem on reddit, but it wasn't specifically against the rules. The admins were doing things like working closely with, even giving out a mod of the year award to, violenacrez, the guy who created and maintained r/jailbait and r/creepshots¹ as well as dozens of similar subs. The material itself was bad enough but it was extremely obvious to everyone that these subs were being used for people to meet and DM each other CSAM.

And then of course that period basically ended with gamergate, for whom reddit was one of the central venues to choose targets and organize harassment campaigns from. Also not against the rules at the time, since the harassment happened elsewhere and was only coordinated on reddit.

Reddit has always sucked.

¹ Both explicitly intended for sharing sexual & sexualized photos of minors

Normal reddit died when Carmen Ortiz drove Aaron Swartz to suicide over persecuting him like a terrorist for downloading a few thousand public domain scholarly articles. (Which Meta and others now do with proprietary, copyrighted material at a volume 1 million times more.)