The way prices are ex-DXB (try to make a 'booking' out of Dubai on the website) it's a lot higher than ex-Anywhere else.
I don't know how much % of passengers on EK planes are UAE citizens/residents, but except in the summer or winter (expat population visiting home) it would surely be less than 50%.
Idk if its nice to overcharge the 'home customers' - but there are MANY airlines which fly into DXB anyways. It might even be to encourage other airlines to fly into Dubai's airport and compete. Keep in mind that EK is government-owned, DXB Airport is government-owned, and Dubai is also government-'owned'.
I know that EK is not public, but if I was a shareholder I wouldn't complain - their revenue model definitely works for them.