"It's almost as if he's trying to show us not what actually happened but how these events might recur in the guilty parties' dreams."

Which logically implies that he [director Errol Morris] isn't trying to show us "how these events might recur in the guilty parties' dreams." Which puts these sticky blood shots in the "this could have happened but it didn't" category.

I think it is a glimpse into the horror of what war can do to regular human beings. I am sure those involved will suffer for a long time from their own memories.