For one thing, the IRA used the M1. The M4 runs east-west. (joke). More to the point, revolutionary republicanism and the IRA existed for a pretty long time. A lot of those who joined the (P)IRA in the 70s were grandchildren of "old IRA" members. True also for many of the international (mostly US) supporters. They communicated in person.
And notice how regional that is, stemming from a history/land divisions that again were regional. Imagine if people were bombing for the IRA world-wide... that is materially different.
Ironically the weapons and funding for the IRA came from international sources, much like how ISIS obtains funding and fighters from international sources. And the IRA did this without the use of the internet in 1970. Two principle sources were the USA and Basque country. https://en.m.wikipedia.org/wiki/Provisional_Irish_Republican....
The IRA didn't target global targets, it's true. The IRA didn't blow up mosques in Syria. But the reason for this is that terrorists attack those who are in power, and the large majority of that flows back to Western Europe and USA. There are no muslim terrorists trying to get popular from murdering school children in Belarus, for example.
For one thing, the IRA used the M1. The M4 runs east-west. (joke). More to the point, revolutionary republicanism and the IRA existed for a pretty long time. A lot of those who joined the (P)IRA in the 70s were grandchildren of "old IRA" members. True also for many of the international (mostly US) supporters. They communicated in person.