Given that the people of Ireland reject that name, it’s a very British thing to deadname them.
Serious answer - no Prythonic speakers lived in Ireland, so there is no proper basis for the name beyond people quoting a Greek who had never been there. It fell out of use for a millennium and was revised by a Welshman who spoke to angels as a way to erase the separate identities of Scotland, Wales and Ireland. His reasoning was that the King of the Britons, Arthur, had conquered Ireland (if he ever existed, he did not). I am speaking of John Dee who also coined the terms British Empire (it stuck) and British Ocean (it decidedly did not).
To expand on Arthur, if he ever was a real person his first historical record was written 300 years after his supposed death and it claims he was a war leader, not a king, fighting the Saxons to ultimately no avail, though the Historia Brittonnum makes sure to assure the reader that’s only because the Saxons kept bringing in new troops and not because Arthur lost any battles.
Given that the people of Ireland reject that name, it’s a very British thing to deadname them.
Serious answer - no Prythonic speakers lived in Ireland, so there is no proper basis for the name beyond people quoting a Greek who had never been there. It fell out of use for a millennium and was revised by a Welshman who spoke to angels as a way to erase the separate identities of Scotland, Wales and Ireland. His reasoning was that the King of the Britons, Arthur, had conquered Ireland (if he ever existed, he did not). I am speaking of John Dee who also coined the terms British Empire (it stuck) and British Ocean (it decidedly did not).
To expand on Arthur, if he ever was a real person his first historical record was written 300 years after his supposed death and it claims he was a war leader, not a king, fighting the Saxons to ultimately no avail, though the Historia Brittonnum makes sure to assure the reader that’s only because the Saxons kept bringing in new troops and not because Arthur lost any battles.