That's not true. As far as the law is concerned, users/providers are shielded so long as they don't take part in authorship. You be as despotic or biased as you want, and you're still not considered the publisher of content provided by another user/provider.
Further to that, the idea that "if you take moderation far enough you become a publisher" is the situation prior to §230, that §230 was enacted in order to get rid of (so that there would no longer be a disincentive for intermediaries to choose to moderate!).
