Section 230 is not about preventing "harm" or anything like that, the specific section just provides civil immunity for moderation/removal of content that is deemed "obscene, lewd, lascivious, filthy, excessively violent, harassing, or otherwise objectionable, whether or not such material is constitutionally protected."

You don't have a responsibility to remove such material under 230. But it gives you immunity to do so, as well as immunity from losing 230 protections for those that safeguard your overall immunity (as a service provider, and not a publisher.)