I know I'll probably get flamed as a "revisionist historian" for this, but here goes.
Simply being in the German Army during the reign of Hitler and the Nazi Party didn't necessarily make you a Nazi. Just like being in the US Army right now does not mean that you are a Republican. It is possible to love your country and fight for it even though you disagree with its political leadership.
Nazi Party membership was voluntary, although adherence to its rules after 1933 was not. Most army regulars, especially at the end of the war, were conscripts, and as such were forced to fight. Many of them were as young as sixteen. It should not be surprising then that as a young man, Joseph Ratzinger was in the army. The news stories that I have read concerning this matter went on to say that Ratzinger was a deserter and was later made a POW by the Americans. This certainly does not sound like the actions of a die-hard Nazi fighting for his convictions.
It should be noted that the Catholic Church knew of Hitler's plan for murdering the Jews and many other groups in Europe. And though they knew of this plan, church leaders made no statement opposing it, presumably because Germany was a Christian country. Pope John Paul II apologized for this inaction on behalf of all Catholics.
I have no way of knowing what young Ratzinger's thoughts were on the subject, but I see no reason to criticize him now for simply being in the German Army, especially since he was probably forced to fight. To my knowledge, Ratzinger has never shown the least bit of anti-Semitic belief.
:twocents: