Anything could have ignited this tinder. But that too. The landscape was prepared to burn by over a century of cascading causes. Including an unprepared and clueless government. And people.
A parallel case btw, are the California fires. Land use, development where it shouldnt have been, political priorities that were blind to physical circumstances, etc.
Topography, more than anything else is the reason the fire was so devastating, in addition to the wooden buildings. People want to live near the coast/beach and the land there is flatter, and is used for agriculture and ranching. It’s the western side of the island with tall mountains behind it, so more likely to be affected by tropical storms.