SPOILERS

The last scene shows the two sons talking together in front of the high school. I don't think Haneke wants us to think about the tapes so literally as to imply that the sons collaborated on the videotapes. However, the younger generation's disgust makes sense on a metaphorical level (i.e. French-Algerian relations) and shows that there is hope for the next generation. I'd prefer to see the final scene as obliquely as possible, and I think Haneke shoots it that way for this very reason. At first I thought that Haneke wanted us to believe that the boys were behind the tapes but now I feel that it's just too pat an explanation.