It remains a defeat because it's "results" still hold and triumphal gloating dominates. When the celebration is conducted as Paul Burke describes, something that COULD happen with a truly united Ireland, it will be a celebration of a battle by those who ancestors participated, "winners" and "losers" both.
Here in the states we "celebrate" battles and skirmishes of our civil war. Union and Confederate re-enactors. Armed, yet. And the only "dead soldiers" are empty containers of beer.
No gloating. We gather to re-enact and to honor the more than 600,000 who died in that war.
I like your idea Paul Burke.