The document I've linked is written by an English speaking government, to convey to other English speakers on how to properly write the name of something within

The document I've linked is written by an English speaking government, to convey to other English speakers on how to properly write the name of something within it's territorial borders. That same writing convention is also used by the local government, the citizens who live in that location, and indigenous population. This is not akin to multiple names for various locations in different languages (e.g. Vienna and Wien). The name of the island in English IS "Hawai'i" as defined by both the government who controls that island, and the culture on that island. Ergo, when writing the term in English, we should use "Hawai'i". Misspelling "Hawai'i" as "Hawaii" is an understandably common error akin to how sometimes people use "Holland" and "The Netherlands" interchangeably (despite one being simply a region in the other). But make no mistake, the name in English for the country is The Netherlands, and the name in English for the region is Holland. Similarly, the name in English for the state is Hawaii, and the name in English for the island is Hawai'i. I find it strange that you are so insistent on this.