Almost certainly, I'd say. A good few years back I read the memoirs of Sean O'Callaghan - "The Informer". He talked about how he grew up in the deep south of Ireland and truly believed in "the cause", but as he rose up through the ranks he found that much of what the IRA were supposedly against, as a Catholic organisation, was actually their raison d'etre. Prostitution, drug running, arms dealing. It was this that prompted him to become an informant - he felt betrayed and tricked.
I'd be shocked if ISIS, Boko Haram, etc aren't exactly the same. Populist with a hidden agenda. Like Trump.