I'm not quite sure what you mean by "pure intermediary". Section 230 does not say that you have to publish all user-generated content indiscriminately in order

I'm not quite sure what you mean by "pure intermediary". Section 230 does not say that you have to publish all user-generated content indiscriminately in order for its safe-harbor to apply. IANAL, but that's not how I understand that Section 230 works. If it did work that way, I think the law would be horribly broken. No site hosting UGC can be completely un-moderated, and therefore by your reasoning, no site with UGC content could benefit from Section 230. Luckily, sites can exercise some measure of editorial control of their UGC while at the same time still benefiting from Section 230 protections. As the OP states, the law is often regarded as the legal backbone of the internet, and its protections for publishers should not be easily dismissed. What Yelp is demanding here is to be a named defendant if they are to be bound by the court decision, which is already the standard for newspapers. I think it's fair to expect to have a seat at the table if the courts are going to be ordering you to modify your site. Particularly because in this case there appear to be questions-of-fact regarding which reviews were even written by the defendant.