The article you link say:
"Since the above mentioned first-release versions of Mobile WiMAX and LTE support much less than 1 Gbit/s peak bit rate, they are not fully IMT-Advanced compliant, but are often branded 4G by service providers. On December 6, 2010, ITU-R recognized that these two technologies, as well as other beyond-3G technologies that do not fulfill the IMT-Advanced requirements, could nevertheless be considered "4G", provided they represent forerunners to IMT-Advanced compliant versions and "a substantial level of improvement in performance and capabilities with respect to the initial third generation systems now deployed"
I get 20 Mbps actual sustained download speed with the 3rd gen iPad (on a non-LTE network), which is substantially faster than what I've had with any previous "3G" devices I've used. It's almost as if it would fit the ITU definition of "substantial level of improvement" mentioned