It's a party piece, lads, probably an encore. If you can't enjoy it for what it is, too bad for you.
Well, indeed.
Tunes are often played differently in different social settings, and this is how it should be. Damien plays here with evident skill and knowledge and I for one enjoyed the different aspects of the tune and styles of playing he went though. Did he go a bit "too far" at the end, possibly or not ...but, that was the whole point of the exercise
There are Irish jigs that have secret lives as "Morris" tunes, airs become dance tunes, English marches become Kerry polkas, a tune played sedately for a dance becomes a rip-roaring bit of fun at a session, and a reel may become a soulful, nuanced tune to savour slowly. Tunes have different lives in different communities, different jobs to achieve in different social settings. I wouldn't play a tune for a country dance in the same way that I'd play it for rapper, and I'll "mess around" with a tune more when playing alone than in a session, and rather differently in a session than when directing people around a room at a dance.
Damian wasn't sat there setting down a template for how this tune should be played, but having a bit of fun and showing virtuosity as a professional musician in front of an audience which appeared to be enjoying it.