You're taking semantics far too seriously, the main point of the thread is not the semantics itself, as you noticed it's just a boy trying say a reviewer also takes participation on the development of a game (which, you guessed, is BS). Whether the term developer applies or not is just detail.
And yes your last example is a good example on how semantics can be deceiving, there's a job called "Tech Writer" in which is usually the one responsible for developing documentation and user experience related stuff, most of them also code.