I think the creature running around Cookie Kingdom (ie the human) should have some sort of ridiculously normal name.
Like Stephanie or something.
So I imagine Stephanie first introduced herself as that, Stephanie.
In Cookie Run: Kingdom, characters have their name end with their race. This is obvious for cookies, but we also see these with others (Maestro sugar gnome).
So in their minds, Stephanie was Stephanie Human, and that worked.
Until Stephanie introduced herself as "Stephanie Baker".
They were a little confused, wasn't she a human? But they rolled with it. Maybe humans had "baker" in their name instead? Cultural differences, and all that.
Then Stephanie started talking about another human with another ending to their name. And at this point the cookies are just confused.
At this point Stephanie is also fed up with having to explain this to every cookie she meets, so she asks if there was something easier to refer to her by.
So now they call her Stephanie Cookie, or Human Cookie.