Your perception and opinions is likely why you don’t know of any adults who fret over third person pronouns. You are not a safe person to bring those concerns up to so no one is going to out themselves around you. I assure you it’s more common than you think.
Generally speaking we’re looking to gain quality of life. If someone negatively reacting is a bigger problem than the internal dysphoria triggers then we take the loss and just quietly hope we don’t have to be around you for long.