Geographical names are political, there's nothing objective about them. Calling them the British Isles implies some kind of ownership, but Ireland is not a British possession. There's lots of other groups where you could apply the same logic, insisting on a name when it offends the people it applies to. Unless you've just bought a large quantity of atlases where Ireland is named as a British Island this would make no difference to you, so why would you argue for it.