As someone who (thankfully) never lived through the horrors of that time, but who thinks regularly how lucky she is that so many people were willing to sacrifice their lives for her I think you raise a couple of valid points.
But a German flag isn't a Nazi flag. To me the two are almost as unrelated as Christianity and the KKK.
I'm sorry it ruined your evening, and good for you for complaining about something that you feel so strongly about. But it was 60 years ago. We often say that 'we can forgive, but we cannot forget'
I wonder how many people truly have forgiven?