My rationale is that it confirms the uncertainty, and above all it is well sourced. It would seem to be a pertinent fact that his place of birth is not confirmed, so arguably sources that give a location are misleading. That aside, the fact that he was born somewhere in the British Isles is all we know, and a source stating that position is to be welcomed. If the consensus is that "he was born somewhere in Great Britain", fine, but please find a source. And BTW, don't forget the source was there and was taken away, so I'm hardly proposing to add it.