Because A.) it contradicts Apple's own published naming scheme and B.) it will be confusing when Apple does release a 4G-network-capable iPhone. Are you going to call that "the iPhone 6G-but-in-actuality-4G"?
Fine then, for you, it is, iPhone 2,2 [or 3,1]
Guys! READ MY LAST POST^^^^
We know. See Engadget.com