The title is inaccurate. It is alleged that he signed up for guest accounts on their network with different laptops, changed his MAC address and re-registered if the IP he was using was blocked (by JSTOR) or cut off of the network (by MIT), and finally connected a laptop in a basement networking closet. I guess you could say that is 'hacking' in the unauthorized access sense, but not in any meaningful sense. It isn't…
How is this not "unauthorized access" "in any meaningful sense"? They blocked his IP, they blocked his MAC, and he hid a machine in a wiring closet to get on MIT's network. What would he have to do to make it "meaningful"?
Changing a MAC address (on a device that you own and control) does not constitute hacking. It is as simple as ifconfig(8) and if you have a consumer router it probably has an option in the web interface to do it.