First, while there s no question that it was a difficult choice for the young Ratzinger, there were many many people in Nazi Germany faced with the same tough choice and they choose a different route than to serve the Nazis.
Now this could be forgiven for your average German, but the Pope would seem to be a position that might be expected to have people of a higher moral fibre than he displayed at the time.
Also, his more contemporary history shows him to be no friend of the poor (a subject that Jesus, remember him, would probably rank way up at the top of the list of priorities of his church) when he fights Liberation Theology in Latin America, realistic methods for the prevention of AIDS in Africa and around the world, protecting child rapists, and other assorted acts of hording riches and power for itself.
72 Virgins sounds like a reasonable belief compared to the belief that killing the poor and making them suffer is a Christian virtue.