its probably because it creates a bit more rise for him . I raised my stack height about 10 mm then it still felt wrong . I then rolled the bars forward a bit till I liked the way it felt and added the 3-4 mm I was short from the rise and also increased the distance from of the top length
Caliper/Lever is what you're thinking of. These wheels are off my Trail bike, so only temporary while my proper DJ ones get here. So there's no point taking off the rotor.