And so how does Kingwell know why people participate in "outright racism, nazism etc"?  Is it anger, is it just to be part of a group like a terrorist group or a criminal gang? What do former believers say? Well what they don't say is that it is an ingrained ideology for them, they join for  MANY reasons. Kingwells problem is (like many) he lumps ALL of these people into one group, one intention-- sad . 
 
Unfortunately ,you see many in the soft liberal left ( yes there are differences not everyone can be lumped into one) believe this linear ,"rational" thought process. It is not that simple. Many are angry because they don't see their lives going anywhere. Ditto some terrorists, people living under abuse-- e.g. formerly in South Africa, Palestine etc.  This is EVERYWHERE-- same model.  Open your eyes.