An IRS-issued free tax filing system has been proposed by both parties since the Reagan admin., so this should not be a polarizing issue. The sliver of funding given to the IRS to study such a proposal equates to 0.02% of the total $80B given to the agency, so no one should worry about our tax dollars being wasted on this. Just as paying a parking ticket doesn't require a third party to help you, filing tax returns should be a simple, cost-effective process that every American has access to.
While the tax-prep industry has flaws, that argument is the shield big government supporters use to obtain more control over Americans' lives. Even if the IRS already has our information, giving it the power to prepare our taxes won't suddenly make it less of a money-grabbing institution. Furthermore, as is the case with the Dept. of Motor Vehicles and public healthcare, it will be a subpar program that makes taxpayers jump through bureaucratic hoops just to pay their taxes.