How did "profession or hobby" or "the right to speak" get into this?
The point was -- only was, only is, only will be -- that when most gamers say "game design", they do not mean designing scenarios or campaigns, they mean design of actual game systems or rules sets, going beyond just RPGs into things like board games, video games, etc. That was all. So when someone says "game design" and they're talking about individual campaigns, most gamers are not going to realize that.
(Just like when most gamers say "railroading", they mean effectively the same thing, and it's not "any planning you do as a GM".)