It has to deal with making judgements about what is right and wrong. See this piece from the Times:
YouTube users can flag any video as containing pornography, mature content or graphic violence, depicting illegal acts or being racially or ethnically offensive. A video is removed — as Ms. Malkin’s was on Sept. 28 — only if a review by the company’s customer support department agrees that it is inappropriate, or that the video is on its face in violation of the site’s terms of use.
But the incident raised some questions about the fine line YouTube’s administrators walk when they decide to respond to users’ complaints about contributions to the site — a mechanism that is fraught with the potential for vindictive shenanigans.