I recall a statistic from about 10 years ago that computer forensic investigators in law enforcement burn out after two years due to the trauma of the images they are exposed to.
- Facebook: it's violating rules? Delete, next.
- Forensic IT on a multi TB disk full with child porn: document every photo, what it shows, extract identifiable faces to cross reference with other content (to check for recurring places and victims), and the process is even more gory for video content. You have to watch every second or the defense can attempt "you didn't watch the video in full where the perp gives the victim an ice cream at the end" or whatever else. The amount of time you spend with documenting a single photo or video is many orders of magnitude worse than FB content mods.