D Day was a very important battle in WW II and of course should be honored but to say the Nazis lost it all on that day is to forget the real decisive battles in Russia that truly destroyed the bulk of the Wehrmacht. The Kursk salient probably being the most decisive of all.
I understand, but imagine if all the sacrifice at Normandy would have resulted in being totally pushed back. The consequences would have been very, very dire.
Until the second Front was established, the victory of Soviet Arms was not assured.