It would help to make things clear if FB in their terms of service would specifically and explicitly excluded public officials from limitations on hate, violence inciting and other otherwise prohibited on the platform speech,and marked that speech accordingly.

Or let an official to explicitly checkbox such exception in his/her profile or may be at individual post level, a la carte style with separate checkboxes for hate speech, racism, etc., and mark such his/her post as made under that exception - "This post is published under the hate speech, [comma separated iterator over the checked checkboxes' values] exception requested by this public official"