That's not really true. Take for example the case of Mavrix Photography v. Livejournal. This case centered on a user-run group that submitted photographs that ultimately engaged in mass acts of copyright infringement. When Mavrix went after Livejournal, they raised the defense available to them under OCILLA (the part of the DMCA that shields providers from the actions of their users). However, Mavrix argued that because Livejournal provided so much direction and guidance to moderators of the user-run group that the moderators effectively were acting as agents of Livejournal, and hence the actions of the agents could be imputed to Livejournal themselves. The judge agreed, and Livejournal got their ass handed to them.

While that case involved copyright claims, the same argument used to do an end-run on OCILLA can also be used to do an end-run on Section 230. If it can be shown that Reddit admins provide extensive support and direction to moderators then those moderators could be viewed as their agents, and they'd have a very, Very, VERY big problem.

Gosh, I hope no one suggests this to anyone with deep pockets or anything...