Utter codswallop. The IRA used fear and intimidation of their "own" catholics in order to keep them in line and maintain their own position of power. They were not ideologists fighting a just cause, they were thugs addicted to power who enjoyed killing and mutilating innocent people, which is why their campaign of terror continued unceasingly for years despite it being patently obvious that northern Ireland would NEVER become a part of the south.
Of course their protestant/unionist equivalents did much the same thing, as did a not insignificant proportion of the RUC, which for me is what makes "The Troubles" such a sad period in what is otherwise a lovely country.
Not trying to exacerbate the situation, but the reason the IRA made any lee-way in NI during the Troubles was due to the fact that they were perceived by a lot of Catholics to be doing more then the RUC or British army in protecting them.
Just look at the video I posted earlier, that man is typical of hundreds of young, working-class Catholics in the early 70's. They joined because they wanted to try and protect their community from what they saw as state-sponsored Loyalist violence that the arrival of the British army in 69 did nothing to abate.
I hate having to go back and reiterate the fact I don't support or the IRA, but I feel that I cannot get the point across that they weren't just gangsters with Republican leanings without sounding like I do support them.
Now the RIRA and CIRA, they're fucking gangsters. The only reason they set of bombs is so they can claim to be "political prisoners" if any of them get arrested. But the IRA of the Troubles had actual political connections and objectives, crime was a means of supporting the cause, not the reverse as is the case today.