I'm having a hard time connecting this to Section 230. So you're saying there should be an exemption for recommending harmful content but only if the content is easier to share than forwarding an email?
Section 230 is a very short section of law, you can read it yourself: https://www.law.cornell.edu/uscode/text/47/230
In any event, it was just an example. Feel free to substitute "HN decides what to show on the homepage" instead.