1) it really does demonstrate a suspension of disbelief
2) it indicates an exceedingly strong bias
this guy is a nihilist, in the classic nietzschean sense. well, i don't want to call him a fascist - that's a little too much. but, he glorifies dominance and submission; he's adhering to a master morality, and that was common in the ancient world. he identifies with these muslim conquerors, and their spencerian vanquishing of the weak. so, when somebody gets in the way of his social darwinist fantasies, they get showered with scorn and derision.
if i were to act the part of the professor, i'd have to tell him he's a bad historian - he's not even trying to be objective. but, these are designed for entertainment, rather than scholarship, and that's not useful - what's useful is to point that fact out.
i wish he had applied this glimpse of skepticism more rigorously throughout the series. alas...
...for, it is now almost done, and i'd might as well follow through with it.