A fee is appropriated, a tax is not. Your government can do what it wants with taxes (e.g. fund wars instead of building roads) but it cannot decide that the radio/television fee will be used for road building (without changing the law).
Every government appropriation is a change in the law. The government passes a bill every year that dictates how money will be divided amongst different agencies and departments. So, there is no way to appopriate tax dollars without a change in the law.
Whether the term used is "tax" or a "fee", it won't make a difference to the pocket that just got picked. If the difference between those terms comes down to the whim of government and its laws, then it remains out of your hands anyway.
