Nothing in my post suggests that Kauai residents pay the GET for rail. But just as Kauai residents shouldn't have to pay for rail (hence, "valid arguments"), so too is it dubious that Windward Oahu residents should.

The debate concerns whether the GET is an appropriate funding vehicle for rail, and there is no single proposal. You seem focused on one form that would preserve the existing surcharge for the City and County of Honolulu, but some suggest increasing the amount of that tax. These arguments are designed, as explicitly stated in my introduction, to respond to various proposals.

Moreover, there are various proposals for what should happen to the administrative fee. You're incorrect about the admin fee helping to pay the Department of Transportation's budget. The current fee collected goes into the state's general fund and is supposed to pay for the Department of Taxation, not Transportation. See the UHERO report: http://www.uhero.hawaii.edu/assets/Mak_RailSurcharge.pdf