&gt; Young people join ISIS not because they are &quot;evil&quot; (what, are they Darth Vader?). They join because ISIS makes a compelling case that the world would be a better place if it was rid of western domination.<p>I will not speak about young people joining ISIS, but I&#x27;ve known people who joined or wanted to join the military strictly to kill. These folks exist. You give them a strong ideological or philosophical reason to kill <i>for</i> and it brings in some of those sitting on the fence. In the case of the US military, I&#x27;ve not known anyone who made it through bootcamp with these attitudes (though I&#x27;m sure plenty have). They actively weed out these folks because, while their main mission involves killing, psychopaths aren&#x27;t usually good soldiers. Groups like ISIS have no qualms in this regard, so these attitudes will survive their equivalent of basic training.