ISIS is a gang. Gangs exist in places that are poor, have poor schools, and have lots of competition for resources.
Which is why when crack cocaine showed up and became very profitable to a select few, lots of people were willing to kill each other to control it.
Every single gang, every single terrorist group, and even overall good militarizes promise this idea of brotherhood and belonging.
I think if we give people something to believe in or be a part of, then they won’t pick something worse to believe in or be a part of.