As we learn more about him, he seems to have had a staggering mixture of motives; he was such a tightly wound ball of hate that we never may truly untangle the real cause of why he did what he did. He didn't much like any minorities. He slapped his first wife around. He broke chairs. He threw angry fits at the office. He may have been a self-loathing gay man.That's a lot of chaos swirling in one head.
Meanwhile, the single best explanation for what ISIS has come to signify was given by The Daily Telegraph's Ruth Sherlock in her piece, "Donald Trump's scaremongering response to Orlando shooting is the opposite of what America needs".
It has become an umbrella term by which psychopaths feel they can justify deranged acts.That makes more sense to me than almost anything else written about ISIS/ISIL.
Isil has become a way for the dangerously mentally ill to find meaning in their madness. They adopt the Isil flag as a cover for their own private motives.