I forgot about Bettleheim ... and Grimm's was very grim.
My host parent's gave me a copy of Max und Moritz when I was in Germany ... these two bösewichter (villains - inspiration for the Katzenjammer Kids) come to a very bad end as you can see:
01_Max_und_Moritz
(full text German/English)
I think the key is the sophistication of the media ... the director of the film Burnt mentions studied under von Trier and others. Film-makers have long been expert at eluding censors - be they government or parent. I think it may be hard to assess exactly what effect a film has ... Hitchcock knew a lot of things his audience didn't.
I think it's also very hard to assess how a child sees something, from our adult perspective.
What happens off screen can be more disturbing than what you see - but that disturbance may not be immediate and so it may be hard to make the connection.
I haven't seen the film Burnt mentions, so I can't say anything about it, but a Google image search is disturbing ...
http://1.bp.blogspot.com/-YqwQ0QddO-o/VC8TyhHq_qI/AAAAAAAAN24/yN7ltt8YXI4/s1600/nightmarish-new-trailer-for-the-babadook.png
this link isn't explicit - it's simply a photo of a child's face contorted (CGI?) in horror or agony.
I do know what passes for PG now is a very far cry from the horror films that kept me awake as a child - compare John Carpenter's Halloween (1978) with modern instantiations of the slasher film, most directly with Rob Zombie's remake of that film. When Donald Pleasance looks up from the window where Nick Castle as "The Shape" has fallen and not finding him on the ground as expected, he answers Jamie Lee Curtis' question regarding the identity of the The Boogie Man in the affirmative ... "As a matter of fact, he is." I was set for many a good night of insomnia. To this day, the theme music or sight of the mask (a bleached Captain Kirk mask) the killer wore means I'll be sleeping with the light on thank you! But I wonder if that isn't a different effect from the explicit violence available? I was scared but obviously not desensitized and I think that is because it wasn't explicit. It wasn't in any way fun or something I craved more of -
I certainly didn't know my mind as a kid, what I could handle and what I couldn't ... that's part of being a kid. And part of being a kid is thinking you are more sophisticated than you are and wanting to impress parents and peers with your non-chalance. I'm also not sure I could assess a child's tolerance for these things. It seems media consumption isn't necessary and unlike real life, is avoidable. I certainly wish I had read and seen some things a few years later and others not at all. The natural course of events brought enough real experiences for me.
I remember reading that Gunsmoke was an early example of media violence, based on the number of (completely bloodless) killins in each episode. What had happened was in the late 40s and early 50s people watched Playhouse 90 and others and then turned off the television and discussed what they had seen. The 50s brought the Korean War and increased violence in the city streets of America and so sponsors wanted to ratchet up the level of television violence in order to keep people's attention and ratchet down the quality so that people wouldn't have that much to talk about and would leave the TV on.