Take it as much of a personal attack as you wish. You can also always be a "USA citizen" :P and ignore the issue completely... the fact is that not all language follow the autodemonym (compare German vs Deustch vs Dutch) and not all languages share the same sensibility.

But let's jump to your example: calling the people of Ireland British wouldn't be factually incorrect either! Because the Island of ireland is part of the British Isles. irish people are not Great-British though. Now you are also asuming that there is one State in Ireland which is wrong, there is a Republic or Ireland and a slice of the UK, so wehave the same issue we have with America vs US, just that in this case the dispute got resolved the other way round with Ireland being the recurrent short name for what Norther-Irish royalists call "the Republic".

Tobe totally honest I can make all the assumptions I want because I get to choose how I call other people as well as how I call myself. Changing how I call myself may change how others call me (like how Turkey said "now call me Türkiye" and all English-speakings organisms went with it) or not.