Whilst I agree with you Simon, I also believe the only reason Jehovers Witnesses ended up in concentration camps was because Judge Rutherford wrote ridiculous letters to Hitler. Therefore the persecution of Jehovers Witness was preventable.
As for the holocaust and concentration camps, it is a reminder of the human ability for evil, and it should be studied by our children and our children's children, and never forgotten. But surely the most important lesson, is that we must teach our children the lesson is to care about each innocent individual and their fate without prejudice.