Second thing: A writer's mind
I don't write screenplays, I write novels. So, I am not entirely the same species, only closely related. And the demands, readers, publishers, TV producers and whoever else in that business pose to writers are simply the same lately. A lot of people think, the more brutal, the more disgusting a work is, the more intense it is. And the more intense it is, the more it sells. I got manuscripts rejected by editors back with the comment "not brutal enough". And the business became shallow in that aspect. Thirty years ago, in Manhunt, Thomas Harris came through with descriptions of bloody crime scenes. All what happened played basically out in the reader's imagination. Today, he wouldn't. People demand explicit brutality. And on stage or even worse in TV, both are visual mediums, it goes more and more splatter. Some writers follow the trend, others not so much.
However, writers are a wide variety. From Harris, who wrote one of the most scaring SKs ever, but is happy to hide from people and whip very normal things up in his kitchen (hobby cooks are not that rare under writers) to that guy in Mexico, who wanted to write a cannibalistic vampire and for research reasons, killed some people to eat parts of them and drink their blood. Most however, don't kill. Writers create brutality in their imagination and they do it excessively. That doesn't mean, for most writers, we do it for real. We don't need to. Because while we write those stuff, we have more than our share of scary brutal thoughts. And most writers I know, feel after writing that kind of work rather the need for a shower, good music and a beer or the dark urge to cook something (which usually not cooked from human ingredients, just to make that point clear). So yes, even the most peaceful writer on Earth is probably able to write something disgusting, brutal and utterly vulgar if it is demanded. And admittedly, I wrote some nasty things too. That doesn't make me a serial killer, just a writer. Part of the job is to shock, to shake the reader.
