Dungeon master wants to be called sir/master

Just a quick question, I’ve never played DnD but I think I get the point … game of make believe via storytelling right?

My girl is about to play it for the first time and the dungeon master has said they are to refer to him as “sir” or “master”

So I’m just wondering peoples thoughts on that…

I can’t imagine playing a game and referring to the story teller as Sir or Master…

It makes me think this guy is sitting at the table with an authority complex over being the person that enhances the play of the game like they’re an equal part of the experience…

I couldn’t imagine a bunch of adults gathered around a table calling someone “sir” or “master”

It doesn’t bother me my girlfriend calling someone this… it’s a game , I just don’t get the idea of wanting to be referred to this way and trying to educate myself if this is normal.

Any thoughts?