[OT] What kind of people went to fight for ISIS and why

I just stumbled on this in my YouTube recommendations and found it quite interesting.
https://www.youtube.com/watch?v=kjf-5wripZs [13 minutes]
The presenter interviews a man who lived in close contact with many people in the UK who ended up answering the call of ISIS to come to Syria to fight for their caliphate. He debunks the main claims made by those who attempted to explain why people would join ISIS, specifically that the volunteers were poor, deprived or particularly traumatized.
It turns out that the people who went to fight ISIS were mostly middle class people who had every reason to expect a successful life in Britain. Most of them were motivated by the opportunity to be part of something bigger than themselves.
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Rhino