Although I was born in Germany, I can not confirm that all Germans are embarrassed to talk about World War II.
If someone travels to Germany, he will inevitably be confronted with German history. And why shouldn’t he ask, about the things german people did to other people in the war?
But it should be remembered that today’s Germans were well educated as children in school about the war crimes and the Nazi era.
Most are tired of hearing about it. So I would not discuss the subject with people I do not know well.
But most importantly, do not call anyone a Nazi, never wear Nazi memorabilia, or do the Nazi salute, not even in jest. This is still against the law in Germany and you could be imprisoned for such an offense.