Plus if Dawkins is positing an ethical premise to his argument for rationalism then he'd do well to indulge in some study of The Frankfurt School, which consisted mostly of Jewish scholars who fled Nazi Germany. They saw scientific rationalism as a double-edged sword, and that the logical conclusion of the Enlightenment could only have ever been the atomic bomb. Scientific progress inevitably involves more and more hygenic, efficient methods for States to kill people. It's to do with rationalism operating according to a logic of identity (the same) rather than difference, and setting up categories of thought that subsume difference within them. It's pretty philosophical but certainly worth reading for those who think that science and rationality are simply de facto good things.