It is not age that matters, but the knowledge

[Issacus Divus]

"Hey, Judean" works because "Judean" is an adjective, not the genitive of the country. "Hey, of Judea", wouldn't work.

"Hi, Ireland's daughter" works because the genitive "Ireland's" modifies the noun "daughter". It isn't used alone.

Hey, Pax. Didn't ask for your all-knowing, all-doubting opinion.

Na, I'm joking. Thanks. I used to refer to full nouns in the genitive

I even used to call myself "ANNAE"