Yep, not disputing that RoI arrivals should go through the same arrivals gate as UK arrivals due to the Common Travel Area. Just think it should be labelled as 'UK & RoI arrivals' like it is at Heathrow etc. I spotted it as I was picking someone up from Cork (must have been a few years ago, now I think about it, as they were on Jet2) and I walked straight past the 'UK arrivals' and went to International arrivals. Only when I finally found them loitering at domestic arrivals did I see that Cork was on the list of 'UK' airports (it was a permanent list, not the arrivals board)
To explain my pedantry , I'm a primary school teacher and we teach them at age 6 the difference between England, Great Britain, the UK, the British Isles etc.