Of course it's not incorrect to use Kyoto as an attributive noun. "Kyoto accent" is perfectly correct. The "rules" laid out in that link are more like common patterns, not prescriptions.
Hard lines rarely happen in the real world. It's best to be flexible such that you can accept unfamiliar instances of familiar patterns without trouble.
Re:GPT Best Practices
by foobarbecue on Tuesday June 06, 2023 @04:46PM
(#36218890)
So... you are disagreeing with your source? It very clearly says "incorrect."
I happen to agree with you and disagree with the source -- "Kyoto man" is perfectly fine in my opinion.
And, fine, let's call it an attributive noun rather than a noun used as an adjective. I was taught the noun as adjective thing in high school but happy to update my terminology. Indeed "layman" is not on my list of acceptable attributive nouns.
Did you notice how your first link says it's "incorrect" to use Kyoto as an attributive noun?