Yeah, the Spice Girls comparison is annoying and not very accurate. The odd thing is that the writer is Toko Sekiguchi, apparently a Time staff reporter living in Tokyo. Of course the point of the article is that China's educated youth going to Japan to find opportunities and the conflicts, concerns, and changing attitudes they face. The writer was trying to get across a general idea of what Morning Musume is about to the average reader of Time magazine without getting bogged down in the details. Who, more than likely, wouldn't know anything about Morning Musume or anything about the Japanese music scene.
And since we're making comparisons, I'm claiming Ginger Spice as England's Miki Fujimoto.