This Planet Money episode[0] has a few short interview clips with Grover Norquist (author of the conservative Tax Pledge). He said that supporting a Ready Return program would be equivalent to breaking the pledge because it is then easier to raise taxes.
Ah, so requiring one to file their taxes is akin to allowing them to own firearms. A check against incursions on freedom. That an industry makes a killing on it is just a side effect :)