Your explanation is the opposite of the classic Lisp usage of symbols. In Lisp, 'foo is not supposed to represent the 3-character string "foo". It can be coerce

Your explanation is the opposite of the classic Lisp usage of symbols. In Lisp, 'foo is not supposed to represent the 3-character string "foo". It can be coerced to that string, but that's not the default or expected representation. Instead, it's supposed to represent an opaque entity, referred to with the arbitrary symbol 'foo. Usernames are much like that.