This would make sense if there's often D Day ceremonies. In the us I think that's all moved to memorial Day, so D-Day pings only as the original event here

You could say e.g. "today is D-Day" to mean "today is June 6th".

But if you said "D-Day" without context people would assume you meant the event in WWII. So yeah, I guess the original headline is definitely misleading, if not strictly inaccurate.