I am not a fan of MacOSRumors.com. Their editorial style reflects that of wannabe Apple prophets.
That said, they raise an interesting point. When G5 is ready for consumer Macs (iBook, iMac, and eMac), it does make sense to migrate pro Macs (PowerMac, PowerBook, xServe) to "G5+"/"G5 Extreme"/"G6" processor (a.k.a., PPC 975). Although I do not have numbers to back up my theory, it's plausible that many people think iBook G4 performs more or less similar to 12-inch PowerBook -- all because they both use the G4 processor, regardless of variation.