Grover Norquist, prominent conservative voice and head of Americans For Tax Reform has talked about the danger of government provided filing services, namely that he believes it leads ultimately to increased taxes.
The idea is that if the govt is saying how much you made, how much you owe, and just giving you a place to click "OK", it's on the tax payer to do the math to disagree, and the govt has incentive to find you owe more. And, taxes are less visible and easier, so if taxes go up or policies change, all the americans just confirming and hitting "Pay" aren't going to notice or be mad.
Or, something like that.
