>>2311454Perhaps, but no more retarded then the only-children/teenagers-can-pilot-giant-fighting-robots trope present in so many other shows. It's an anime thing, I just learn to live with it, even if it does push the boundaries of suspensions of disbelief.
Beside, big burly men assassins just wouldn't have the same "charm," for lack of a better word, that cute young girl assassins do.