I'm curious as to the reasoning here. I know the word "master" has some seriously negative associations when opposite the word "slave", but that's not the case here. Nobody that I'm aware of calls D&D or other RPG players "slaves". If anything, a good GM is there to serve the players, not the other way around.

Edit: I support replacing usages of the paired words "master" and "slave" so as not to reference the very real history of slavery. I'm also totally fine with using "referee" instead of "game master". But I'm concerned that other senses of "master", like "master craftsman" or "gold master" or "game master" which refer to mastery (of a craft or some such) and don't (to my knowledge) connote "master/slave" are being lumped in here.