I'm sure he didn't mean it that way. I can also remember quite a few people almost upset that more tories didn't get killed, especially the prime minister.
It was down to a democratic vote. The majority of Irish counties (32) voted for independence from Britain, but the vast majority of people in the six counties of Northern Ireland voted to stay with Britain. That's why the split happened in 1921. Borders don't necessarily follow geographical...
I'm surprised anyone is surprised by his views, considering that he comes from (London)Derry, but chose to play for the ROI. Surely, that tells you something.
As someone else pointed out, the Queen chose to meet McGuinness and shake his hand, despite her cousin, Lord Louis, being murdered by...