Legally, I don't think DVC can roll the tax in to the dues, according to Hawaii Law.
They can (and do) roll any property taxes in to the resort annual dues, but this isn't a property tax... it's a resort tax. It pays for the public beaches that the resorts use. (Most, if not all, beaches in Hawaii are public) The logic is that the person staying at the resort is the one using the touristy (beaches, etc.) amenities, so they should be the ones to pay.
Hawaii law is written that the person responsible for paying the tax is the person staying in the room. This means that if they roll the tax in to the dues, then they are incorrectly assessing the tax, since the Hawaii owners aren't always necessarily the ones staying in the room... they could be renting the points out, or using them at one of the other DVC properties and someone else is exchanging in.
I agree that isn't how it's typically done at DVC, with each resort owner paying for their own resort's amenities, but that is the way it's codified in to Hawaiian law, so that's the way it must be. Aulani owners will still pay for the private amenities of the resort...the pools, the mini water-park, etc. But this is a tax for the public amenities provided by the state...the beaches, etc.