There exists no distinction between "publishers" and "platforms" as far as Section 230 protections from online liability goes. It's entirely decided by who produced the content: users are responsible for content that they upload, the sites hosting user-generated content are not. It doesn't matter if the site selectively promotes, or otherwise acts as a "publisher", so long as it's the user's content.
Ah yes, US laws are the only laws applicable to Google.
I should have prefaced that with "outside the United States": notably UK moves the bar to the middle, which will put Google in legal jeopardy (and libel cases!) there.
https://www.eff.org/issues/bloggers/legal/liability/230