Well, the guy making this thread tried to include reviewers of games...
English might not be my native language, but the internet is english and developer has a meaning in this context. Since maybe 20-30 years. And that meaning is writing code. If you do html, you are a web developer, if you write software, you are software developer, if your software is games, you are game developer. I would guess it started with some coders looking for a fancy word.
Do creators of board games and table top games call themselves game developers? I think they tend to go by game designers.At least wikipedia calls the inventors of such games designers. But board games are a lot older then the computer stuff. And that is the thing , in computer context lots of words are repurposed. Like mouse. Or developer.
What kinda was tried here, is to step back and reenter with descriptive meaning of the repurposed word, to include additional meaning. Just look at that citings of 18th century meaning of the word developer.
I could also try to rename developers as writers. They write code, do they not. So they are just like journalists, book authors and other writers ;-)