I remember the IRA, and did quite a bit of reading on the history before the 60s. It's the only war of terrorism that I lived, watched ... in the end, what was it proven to be about? Not religion, but oppression. It just so happened that the ruling class was CofE and the oppressed class was RC - for centuries! Was the Church involved? Yes. But the root cause? Oppression of an entire country, an indigenous people, by an outdated colonial ruling class.
It's all about money and power - religious fanaticism does not exist in a vacuum. There is a reason people turn to it, just as they do to any fanatical ideology. Sound familiar? We know that cults recruit the weak.