You miss the point as do most in the US, and Streido will agree, the Majority of the population in Northern Ireland wished to be British, so the British army (and mostly Irish manned police) were NOT on anothers soil at all, as they were on British soil as would be defined under the UN section on self determination.
Well technically yes they did want to be brits, but then these folk in the northern 6 ( i think) provinces of Ireland were all protestant and Anglican decendants of Lowland Scots and English settlers who "invaded" in the 1600's after Englands king decided he wanted to rule Irleand as well as england wales and scotland, good old Henry 8th again, the fat bastard. Most irish catholics were forced into the southern half of Ireland but continued to resist their new rulers from england. After many wars and battles eventually the south was given up and declared the irish republic but the north, still populated by the decendants of those protestant invaders wanted to remain brits so given the north was mostly all consisted of these folk it was declared british since their heritage was british, historically it was not british tho.
Imo the whole of Ireland ought to have been given a vote on the north, not just the north. In fact Oreland ahould never have been oartitioned at all in the 1st place, the brits shouldve apologised and gave back ALL of Ireland instead of just the south. If those of brit decent wanted to remain brits then england should have offered them refuge in england where they couldve lived on as brits and irelamd couldve got back to being ireland and irish.
The situation is now that experts predict the protestant majority in the north will be overtaken by the irish catholic minority very soon due to birth rates over the years so sooner or later tje people will decide to re-unite ireland, probably peacefully thro a vote on their nationallity, unless London blocks it, then the war will start all over again.
As for IRA not wearing uniform....they were a resistance army. The French resistance in WW2 wore no uniform yet we dont condemn them, we applaud them for resisting the invading forces and trying to win back their nation. The SAS and undercover army and police wore no uniform either. You cant have a resistance army if you broadcast that you are resistance, cant work if your up against a superpower type nation with better means, money, power, wealth and numbers than you have, you could never win.