I thought it was illegal alien grass that was the root cause. Some variety that is alien to Hawaii, and is somehow drier than other, native, grass varieties.
I read that, too. As a retired Horticulturalist, I can tell you that’s BS. Hawaii’s grasses/foliage is just as combustible when dry.
There are no plants native to Hawaii.
Any field that was plowed for decades and then left to return to its natural status without cutting the grass or creating a firebreak can result in what happened. The grass in the fields to the north of town grew right next to the houses. Grass grows when watered (rain) then dies in drought. One spark and high winds is all it takes.