The Marriott website reflects the move (it is hidden quite well), in the top left on the Marriott website is the official branding of "Marriott.com / Marriott Hotels & Resorts / Hong Kong / Resort". Presumably this comes with additional fees, that the hotel is willing to pay. As such it is official and so there is nothing much you can do except vote with your wallet if this is a problem, and hope they don't start adding on resort fees.

It seems a bit of a shame, but to switch it around we could be happy that the hotel is doing so well and has become a destination in its own right - a rare success story in these difficult times perhaps?