Because "compelling evidence" can be easily fabricated. Just ask all the writers that have had their works expunged from the Internet because an ex-wife, ex-wri

Because "compelling evidence" can be easily fabricated. Just ask all the writers that have had their works expunged from the Internet because an ex-wife, ex-writing partner, or angry reader decided to claim copyright infringement in order to mess with them. It happens all the time. The valid affidavit requirement in the DMCA is a strong deterrent to this kind of nefarious abuse.