... even in the case of Pearl Harbor, I fail to see any celebratory note there. It is an "observance " to me. D-Day, on the other hand, gives some merit to the celebratory in light that it was ... the beginning of the end for a tragic era in our history.

I agree with Whit in this.
Memorial Day, Veterans Day (Foremerly Armistice Day,) and certainly Sept 11th should be observances, not anniversaries.
On the other hand, case by case ..... Hmmmmm!