Explaining this now because I know people are going to be confused: The distance to Japan is from Rotuma, a far outlying island of Fiji, to Minami-Tori-shima, a very far outlying island of Japan. In fact, many countries on this list are closer to Rotuma than the main archipelago of Fiji, so that is where they are measured from, which might help explain some distances.
Yes, Fiji is closer to Russia than it is to places like Brunei, Vietnam, Singapore, China, or South Korea. Remember, Russia extends much farther east than any of those other countries, and the Pacific Ocean is very wide. (And Fiji owns the island of Rotuma, as explained in the sticky comment)