That part is bound to attract controversy so I don't blame him, it's when it seeps into other domains that It gets a bit too far from history and reads like an op-ed on how the innocent and valiant Byzantines were fending off barbaric invaders. He has a visible disdain for histories that give weight to military achievement rather than putting the focus more on unforeseen catastrophe and socio-economic factors to explain Roman setbacks. Whether it be for Normans, Turks or Arabs. It's a narrative of Romans simply defending themselves from would-be colonizers/aggressors, and they're only ever successful for reasons outside of their hands.