They do not make the point in their article but the current positioning of U.S. Marines forces on Okinawa, while marginally contributing to regional stability, makes the island a guaranteed magnet for Chinese intermediate range missile forces, likely pinning the Marines down and certainly putting Okinawan civilians at risk. If Chinese expansionism (if that is what the Chinese military build up represents) is to be deterred, then it has to be in a manner that is hard to attack.
Besides, what did the Okinawans/Ryukyuans ever do to end up at the receiving end of all this, aside from living on an archipelago positioned in between China and the Japan main islands?
Then again, that is the question everyone has been asking since, oh, around tail end of the 1970s.
Later - I have it on impeccable authority that Professor Mike Mochizuki is just Mike, not Michael. I suppose a major edit is in order.
Later still - While I am on the subject, Professor Mike Green of CSIS is supposedly in town...and Michael Penn's Shingetsu News has a stunning news report on the Foreign Ministry's program to ship Fukushima agricultural products out as foreign aid (Link).