I studied the troubles from a sociological perspective in college and personal interest. From what I studied and have seen, it was a civil war for the PIRA as they were organized as a traditional military unit. Once this became untenable due to infiltration they broke out into ASU (active service units) and became more how they were seen through the troubles.

Although the the British government never formally recognized them as a military force, the PIRA were given essentially everything they asked for in terms of being military prisoners of war except for formal recognition. This status was given sometime after the hunger strikes. To this day, splinter cell members of the Provisionals such as the RIRA are given full “political status” to use their term. This I feel speaks magnitudes to how the conflict is like a civil war. It was an urban civil war which attests to how messy and prolonged it was.

(I use past tense due to the GFA which brought an end to hostilities in 94 but the last British combat unit didn’t leave until 2009; if anyone is Irish or British and reading this I mean no offense by anything said)

Additionally the provisionals sprung up after the Bloody Sunday massacre as a police force to protect themselves and the catholic communities. As things escalated with the police force of the time (the Royal Ulster Constabulary) so too did the PIRAs operations eventually resulting in a de facto declaration of war via violent action.

Long story short, I would say yes.