The need to know is like the need to drink. In order to survive you need liquids for your body and information for your mind. But not all liquids are good for you, nor is all information. Guzzling everything offered without discerning the health effects is an unwise approach. Free speech does no mean you have an obligation to know all the horrors of the world, either. We can examine evil in the abstract with occasional exemplars; it's not necessary or desirable to immerse oneself in graphic violence. I am sure that those on the inside dealing with this stuff have well developed protocols for containing the psychological and spiritual fallout; the rest of us can be thankful that they are doing their job to protect us from having to confront the worst of the worst.