to be clear: he should be deconstructing the islamic dark age myths the same way he's deconstructing the christian dark age myths, but he seems to have bought into it to an extent, in addition to making a conscious decision to give it a wide berth. and, maybe there's something to that - maybe, by approaching it with kid's gloves, he's let his guard down and fallen for some of it.
he might think he's "showing respect" to a "foreign culture", but it just puts islam in a lower level of analysis, at the bottom of the academic hierarchy. if he's willing to do proper analysis for western history, he should be willing to proper analysis for islamic history, as well; that he won't is a lack of respect for their intelligence.
it's a perfect, textbook example of orientalism.