I guess I am not seeing any real support for the thoughts and feelings of the character being the exclusive province of the player, especially when there are all sorts of rules elements that like frightened, charmed, Bardic Inspiration, and Vicious Mockery that imply they effect character emotional states. Is dragonfear not actually fear? It's something the player is instructed to consider for their character, but there's no real support for it being completely unconstrained or solely in the player's hands.
Is the contention really that D&D 5e stands alone in the traditional RPG space of giving players unilateral say in the character's thoughts and feelings? It's certainly not case for Vampire, Shadowrun, Legend of the Five Rings or previous iterations of the game. Is there some passage I am missing in the DMG with stronger advice on this?
Once again not arguing for stronger social mechanics.