Okinawa and the other Ryukyu islands are to the rest of Japan somewhat like what Hawaii is to the mainland United States. Both are sun 'n' surf destinations for the multitudes, with local cultures that are perceived as exotically different, but not threateningly so. The natives speak your language, use your money and are mostly friendly enough. What's not to like?
One main difference is their respective images in the dominant pop culture. "Baywatch Hawaii," "Hawaii Five-O" and other Hollywood shows depict Hawaii as more glamorous and paradisical than the American norm. Even the criminals dress as though they are on a tropical vacation. You don't see that in Cincinnati.
Okinawa, especially, has gone through a different sort of cinematic evolution. The horrific Battle of Okinawa, fought in the closing days of World War II, has inspired many a heart-wrenching film, including "Himeyuri no To (Tower of Lilies)," the 1953 Tadashi Imai weeper about girl students drafted as nurses, whose real-life counterparts died by the hundreds after immense suffering.