While there may be good reason not to have a 2G/3G/4G phone transmitting from orbit, I'm not so sure the same problems would apply to an Iridium transceiver. Iridium is a global system with dedicated worldwide spectrum. There are no terrestrial "cell sites" to interfere with. The Iridium system utilizes satellite to satellite relay to handle handoffs, as long as the process happens quickly enough this should not be a big problem. Even though the Iridium transceiver on the spacecraft was referred to as a "phone", it will more likely be a data modem using one of the burst data capabilities of the system. This would make more sense from a power and size perspective and an entire message could probably be sent during visibility of a single sat, negating handoff issues.
Of course, this only deals with the technical issues. There are probably regulatory ones as well. Iridium transceivers have been used on aircraft for many years now, extending the application to LEO should not be that much of a regulatory stretch.