By pounding the question, again and again, to get a simple answer to the 'why', we want to believe it so much that there's an excusable explanation to even the most inexcusable events, rather than accepting the fact that pure evil does exist. To relentlessly pursue the truth, to know more, is to give a face to those people we hear about but never think are relevant, to make connections, to understand and be understood.
"Go back to what you love, things that darkness can't take away."
All these are important messages that shouldn't be buried so deep under the buckets of gore and guts that viewers are too grossed to see. It's like one of the most common mistakes we make in writing essays - introducing a fairly perceptive and novel idea but failing to elaborate it to make it clearly understood, within the limited word count.