Why do you take Mr. Leavings  claim at face value?  What verse is he referring to?  Just like in Christianity, historical context is important when looking at a text.  Muslims approach the Qur'an  much the way Catholics approach the Bible, in that many supplementary traditions and commentaries written over centuries  are used.   This phenomenon of literal interpretation of every verse without any historical context, is a modern practice that began in the 20th century, and  has never been practiced by any decent percentage of Muslims.