Every operation system has some kind of security tools. Each one of them have different purpose but all of them have same score – protection. In Facebook case there is big question mark.
Should Facebook have some kind of pre-check on all content? In case of photos this pre-check works quite well. Main forbidden things like pornography and violence have little chance to reach internet but there is almost no pre-check of videos. It is understandable. It is so much complicated to check videos. Probably no algorithm can do it and Facebook would have to check every video by person. Question is should Facebook do it.