Unlike Greek drama, the mystery plays did show violence--the murder of Able, the crucifixion of Christ. Biblical plays set a precedent that is abused today, but still is part of the legacy of dramatic freedom bequeathed to the culture. There is nothing morally wrong with the fencing scene in Hamlet, a battle in a war movie, or a death scene when the story calls for the character to de. The Greek perception that extreme violence can be an aesthetic distraction is still valid, although the problem is not so much the violence itself but how the violence is portrayed and what its effect is on the audience.

Gene Edward Veith, Reading Between the Lines, p. 158

I suppose the reasons for the use of so much violence in modern fiction will differ with each writer who uses it, but in my own stories I have found that violence is strangely capable of returning my characters to reality and preparing them to accept their moment of grace. Their heads are so hard that almost nothing else will do the work. This idea, that reality is something to which we must be returned at considerable cost, is one which is seldom understood by the casual reader, but it is one which is implicit in the Christian view of the world.

Flannery O'Connor, Mystery and Manners, p. 112