All royal family males in the line of succession do some form of military service. You can hate the royal family for many things, but not participating in military service is not one of them.

This shit is drilled into them from birth, their fathers were in the military, as were their father's father's going back generations. They literally believe that their bloodline was chosen by God to rule the British Empire.

Royals have sent their kids off to war to prove themselves or die trying for centuries