Do not forget the sickening American morbid fascination with violence and delinquency - manifested inter alia by making idols out of social outcasts and criminals - and the class of intellectual commodity producers (writers, film makers, singers) who cater to that morbidity.
Oh, I wouldn't say this is particularly American. Western classical and medieval literature and myth is chock full of pretty gruesome stuff that people really got into. Try reading some saints' lives; among other lovely (but thoroughly mundane) acts you have saints being grilled, torn apart, and (my favourite) being mortar-and-pestled to death. I think there were some popes who forbade some of the more extreme forms of mortification of the flesh, but it just kept coming back.
Besides, I think this "morbidity" could be healthy in reminding the viewer just how mortal we all are. At least, it worked like that for me.
Todd