The nemesis is someone you know.

Rating: 7/10 (8 August 2011)

This reminds me of Jorge Luis Borges' ability to misdirect his audience with facts, histories, that simply aren't true. I've read an adequate sample of the reviews and I find that many if not all draw conclusions (call them "suspicions") about the film using the backdrop of real history - the audience is necessary to conclude this film.
I don't think there is any lesson or allegory in this story whatsoever. The entire story and all that it insinuates about the future serves the art and philosophy of film, not history. The reason for my opinion is the Narrator. I don't want to pepper this review with spoilers, so I will just describe what the narrator is: an omniscient, omni-prescient that provides an early caveat that his memory is dim. The audience is NOT transported to some view outside of the narrator's own recollection or design. No scene plays out without breadcrumbs from the narrative. The "evil" in this story is the ambiguity of its source, the narrator. Worse, the narrator's "dim" memory may just be his way of NOT saying that he himself is the nemesis.
I find it especially wry that one of the last scenes discusses how the towns-people, the rumor-mongers, fall into fevered conjecture about the events that transpired, not unlike the reviewers of this film. This gives the film a palpable sense of Borges and my conviction that we have all been duped by Haneke. Haneke's own words: "Every argument is powerless against feelings. But every interpretation is also correct, because it occurs in the mind of the recipient -- in your mind, in this case. In that sense, you have contributed to the film -- hopefully." Everyone seems to project history on this story. Keep in mind that this film is even more fictional than, say, "The Titanic". At least the The Titanic was based on a real event in history. The White Ribbon is based on a completely fictional village. Even so... we all knew what was going to happen to the ship, but we didn't know what was going to happen to the village - not to worry; there's an archetype, Nazism, to ride like a hobby horse.
The Narrator is speaking to the audience. Whenever he fails in providing a fact it is not because he doesn't remember, but it doesn't suit the construction of the fable. The narrator is outside of the fable alongside each of us.
Who committed all these acts? Who withholds the answers? Who is telling the story? The nemesis.
Any allegory in the fable is complete misdirection; what matters is the psychology of projecting it on each viewer; every ambiguity, every unsolved (undisclosed) puzzle, propelling every individual to make sweeping statements, grasping. I know that I am correct... after all, Haneke says I am. Quotation taken from Der Spiegel interview.