Thomas M. Leitch has argued that the disavowal of violence has become a generalized feature of American films, especially as those films have become more and more violent: "For as representations of violence grow more clinical or shocking or disgusting or threatening, American films have developed an immensely sophisticated battery of techniques to disavow the power of the very images they are displaying onscreen."From an excerpt of David Schmid's Natural Born Celebrities: Serial Killers and the Hollywood Star System. Like the above passage, it's got a lot of "kind of obvious but also kind of interesting" bits in it.
Leitch provides a detailed discussion of the techniques of disavowal used by contemporary American films and summarizes them in the following terms: "Violence can be rendered acceptable to a sensitive audience by being ascribed to an evil Other, or by being justified in rational terms, or by being limited in its effects, or by being stylized through narrative conventions or rituals that deny its consequences, or by being rendered pleasurable through appeals to aestheticism or masochism or eroticism." Film uses these techniques, according to Leitch, to deny personal responsibility—both the responsibility of the agents of violence and the responsibility of those who watch and enjoy the representations of violence.