I think it's important to remember that history bears little relevance and there is no mental block because if it. Not many Ireland players or fans cared about the whole QF stigma. The Ireland team was the very best we have seen in the country, and can hold their own with any other team in world rugby.
If history was such a factor we wouldn't be watching the current United team capitulate week in and week out!
There does imo seem to be an undercurrent of (dare I say casual England rugby) fans who couldn't wait to stick the knife in and claim Ireland to be chokers, quite why I'm not sure. The true rugby fans I know recognised the Ireland team to be incredibly strong who were simply marginally bettered in what was a highly competitive game.
Keep in mind, as a country this is the only true united sport of significance. To many of us who grew up in times of division, seeing a united Ireland represented, made up of people across communities that were able to set aside their differences, means more than outsiders could understand. An Ireland RWC victory would have been a huge moment, further breaking down social divides, so it does mean something to the people of Ireland. Those dismissing a competitive 4 point loss to the best rugby nation in history as choking is frankly insulting.
Not aimed at anyone here directly btw, rant over