Do they make this "silent retard" choice so that they don't have to personalize the player character that much, much less of a hassle?
I'd say having selectable dialog options work better, and you don't even need a voice actor for the player character to not break "immersion" that the hero represents the player
(yes i am aware that there are dialog options in Dishonored, but you don't really question anything, it's like, kill this person because reasons, do this because reasons. )