&gt; I don&#x27;t understand why we shouldn&#x27;t believe what&#x27;s coming straight out of ISIS&#x27; mouth.<p>Accepting it doesn&#x27;t really answer much.<p>&gt; ISIS has said they&#x27;re killing us because of their interpretation of a book written in the first millennia.<p>Yes, and if we accept this, we are faced with the question of what makes particular people in particular times and places likely to accept and act on messages like this, and what circumstances enable them to be successful when they do. Daesh isn&#x27;t the only group to promote an ideology like this based on interpretation of some ancient religious text (nor is the phenomenon of groups trying, or even succeeding, in doing that limited to the Middle East, or the Islamic world, nor are the Quran the only text which has been used in this role.)<p>Nor, for that matter, was Daesh (though it had a different name!) new to this when they first started achieving real success -- they had similar goals and interpretation of Islam before they became known as al-Qaeda in Iraq, when they were known as al-Qaeda in Iraq, and when they rejected their affiliation with al-Qaeda to style themselves first as &quot;the Islamic State in Iraq&quot;, then &quot;the Islamic State in Iraq and the Levant&quot;, and finally &quot;the Islamic State&quot;.<p>&gt; When someone shoots up a Planned Parenthood, however, he doesn&#x27;t even have to make a public statement and the same people are quick to blame Christian beliefs or rhetoric and immediately accept the ideological reason for the violence.<p>Women&#x27;s health clinic attacks by violent religious extremists with an overt religious motivation are a recurring pattern in the US; assuming that another such attack is part of that pattern rather than breaking with it is not exactly a giant leap. In any case, the ideology behind the attack and the conditions which made the attacker susceptible to adopting that ideology are distinct issues.<p>&gt; Why don&#x27;t we say that gunmen attack Planned Parenthoods because of income inequality in the United States?<p>Actually, lots of people on the left -- the only people who generally acknowledge the overt ideological motivation of violence of Christian religious extremists -- point to social factors like income inequality and persistent poverty as among the factors that make people susceptible to that extremism (as well as pointing to deliberate acts by certain political elites to fan that extremism and channel it for political ends as contributing to the uptake of the extremism.) These positions are complementary, rather than incompatible.