Which contemporary examples (i.e. within the last 50 years) are you referring to? Journalists have been threatened with imprisonment for protecting sources from government subpoena. But the sanction is for refusing a court order, not because of the publication content.

https://archives.cjr.org/opening_shot/opening_shot_july_augu...

And in any case, a publisher is different than a utility or a platform. Social media users are already punished for publishing illegal content (libel, copyright violations, etc). How does making Facebook a "utility" change that?

If it is as your say why would you object to Mark Zuck being personally liable for all content posted on Facebook? If anyone slanders anyone else and his platform publishes and disseminates it, why should he not be considered responsible?

How would a law that holds Zuckerberg responsible in the fashion you describe not be applicable to every website operator and Internet service provider?

It would not be applicable to those who only “censored” illegal material in response to a court order. The difference being whether the operator decides to “censor” content themselves for their own reasons/agenda.

Same as newspaper vs postal service.