Makes sense, to be honest. China, Korea, Russia, and the USA are some of the few countries with the ability to vet phones from local companies. You don’t want your military being dependent on foreign companies, especially if those foreign companies may be subjected to infiltration or secret orders.

The USA has been shown to spy on its allies, so if I were the head of a military in a country that produced its own phones, I would ban iPhones in the military too. Most countries don’t have this luxury, unfortunately.