This is a brilliant movie, but I can see it being frustrating for many people not familiar with the historical range of conscientious objection to violence and the state. Thus, it can seem like the main character is engaged in an act of selfishness that places his own morals above the good of his family. And it is true that most of us could not make the decision - or even come close to making the decision - that he made. This has been the dilemma for such people for a long time. That is part of the power of this film - it does not provide easy answers. It presents the dilemma and the arguments without giving a clear resolution, or at least a clear statement of what is right. The review in the New Yorker misses the point badly by focusing on the depiction of just a few Nazis - the fact is that the film portrays Nazi Germany as more than a caricature - it is the reviewer who only sees a caricature.
There is a long history of people who have made such self sacrifices not as part of a movement or with hope that their action would change the world - consider the two Hutterite boys murdered by the U.S. army for refusing to put on a military uniform during WWI - but acted simply because their conscience would not allow them to act otherwise. There is great suffering in his decision, and had he decided to simply give the oath that would have saved his life, none of us would condemn him. The film does a brilliant job of depicting this without trying to create a saint.