[rustler]

That's a fine distinction, but what word would you use to describe something that's a product of Hawaii but not ethically Polynesian? Like Hawaiian pineapples, or loco moco? On the islands you could just call it "local" but on the mainland that wouldn't make any sense.

[mduncs]

One answer is undeniably clunky, "these pineapples are from Hawaii."

The AP's style guide uses Hawaiian as an adjective.

It is a messy thing when typical ways of speaking English conflict with nuances.

[rustler]

If you can't suggest a better word than "Hawaiian" when someone wants to say an adjective meaning "from Hawaii", perhaps you should keep your peace?