That is also part of why I like things like Ferguson's review. It gets the point across. Someone did the analysis and wrote down the results. Or top-down overviews of crime. I don't think getting too dark really adds anything to it but it might come with a greater risk of reader attrition.
I mean, obviously, someone should be free to write something dark, freedom of speech, but when it comes to getting regular people to read something, that might be an obstacle.