Do you say that Joseph Ratzinger was actually a Nazi, or just that he was a German soldier in Second World War? There's quite some difference.

The German army was just German army, not specifically a "Nazi army" even though the country was lead by Nazis and even though modern click-baiting headlines equate the two.

As far as I know, Ratzinger had nothing to do with National Socialism beyond what was compulsory and unavoidable under pain of death in Nazi Germany (i.e. being drafted).