If you are charging for publishing the content (ads) then you should charge enough to cover the vetting. If you are not charging (comments) then different rule

If you are charging for publishing the content (ads) then you should charge enough to cover the vetting. If you are not charging (comments) then different rules apply and you must take it down if reported for certain things (copyright infringement). If you are not charging (comments) AND you create your own content (news) then different rules apply and you must vet the content for certain things (libel, hate speech). If you are charging for content then you should probably also ask for whatever supporting evidence is required to do a reasonable job of vetting. If someone lies and provides a false release and you have a reasonable vetting process then you will likely be able to use that process as a defence.