This should not be surprising. It has been done for years with utilities. Go out and look at a power pole. For an investor-owned utility, everything on that pole is taxed - pole, insulators, hardware, crossarms, etc. If it's producing revenue it's being taxed. They have simply confused cell phone installations with others, but then a business system is doing the same thing - generating revenue (directly or indirectly).
Amateur installations, however, should be exempt. 73, Kim - WG8S