The point I was trying to make to John was that Nationalists are not the same as PIRA members. I know/knew many fine Irish Nationalists. I know/knew no IRA members.The equivalent of the IRA would have existed in England had the Nazis won in 45. Their methods were abhorrent but they were an inevitable consequence of the history of Ireland in the last 400 years.
I agree that even a cursory glance at the history of Ireland would explain why the PIRA existed though I'd argue that that explanation isn't the same as justification.