For the first part, I can tell you for a fact that the MAJORITY of the Scottish fans who support Celtic have NO INTEREST at all in the IRA, you may disagree but it's a simple fact evidenced by the very few people inside Parkhead who sing such songs. If there was such a massive depth of feeling surely the whole crowd would be singing "Ooh ahh up the RA"? I know many many Celtic fans and none of them are part of the CSA, GB, Ultras or the like, and none of them go to Celtic park to sing about the IRA.They go to watch football.
When I talk of the outside world I am talking about the world outside of Celtic FC. People see the Provisional IRA as terrorists plain and simple, there are of course a few people who will see them as freedom fighters but they are in the minority. Are the PLO viewed as Freedom Fighters? The Tamil Tigers? The Red Brigade? The Baader Meinhoff Gang? ETA?
If you stopped a hundred strangers in the streets of any European City and and asked them who the IRA are, how many do you think would respond "Freedom Fighters" and how many would respond by saying "terrorists"?
For the final part where you say "I have to say that I in turn would conform to whatever the club decided regardless of whether I actually agreed with it or not ". Well the club has asked the fans to stop, Neil Lennon has asked them to stop, even Jock Stein in the past asked them to stop, so i'm afraid there is ample evidence that the fans singing these songs don't really care about the club, all they care about it would seem is their own political ideals, they want the right to sing what they want and will not be told what they can and cannot sing, that does not sound like a real Celtic fan to me, if they are willing to put their own ideals ahead of the club then they cease to be real fans.