Those fees are mandated taxes that they have to charge - much like sales taxes. Is the retailer/seller the one responsible for charging you the tax? No - they are simply acting as tax collectors for the various Governmental agencies that demand they collect said tax. I do not hold my motorcycle dealer responsible for the sales and license taxes that the State of California charges.
Your motorcycle dealer may pay property taxes on his buildings. Does he add that as a fee that he charges you? In the specific case I mentioned, a car rental service charged me a fee for the property taxes on the cars -- this is a tax, but the company must pay it whether or not I rent the car, so it is a cost of doing business, not a tax imposed by a government entity on my rental contract.
But back to phones, in a recent T-Mobile phone bill I see the item:
"Other fees and government-related Obligations"
This is explained as:
"These fees relate to your service. They may be imposed on us and passed through to you pursuant to your contract"
This falls far short of a claim that the fees are merely a pass-through of taxes imposed on T-Mobile that are specific to the service that T-Mobile supplies to me.
The bill also includes an item "Federal Universal Service Fund". Once again, this is a charge imposed on the carrier. The FCC does not require the carriers to pass this charge through to end users. In other words, it is a cost of doing business. It is also predictable and applies equally to all states (so could be included for advertising purposes in all states).