I imagine the proximity of the Arab world to Europe had something to do with it. It’s much easier to talk about your “adventures” and mentorship abilities when you can travel back and forth and get the reputation for being “real.”

And just like most gangs in the world, it’s usually formed of initially oppressed diaspora - migrants and immigrants - to form community and protection but without any recognition of class warfare, you’re prone to just criminal behavior regardless of what the purported beliefs and code of conduct are.

Europe is also one of the US’ closest allies and has the most direct history with the Islamic world compared to the US.

So location + proxy enemy + real enemy + class