I don't buy it. We have many existing laws and spending programs that make us worse off than not having them (or, equivalently, leaving it up to the market rather than the taxpayers to provide them). The free market is known to work well enough, and broadly enough, that demanding "What would you replace it with?" when someone proposes ending one of those laws or programs is un-called-for. (If anyone really does doubt that the market will do better, the thing to do is to try it and see, not to demand proof that can't exist because the change in question hasn't been tried recently.) After a few repetitions, I simply lump the asker in with the kind of troll whose reply to every comment is "Cite?" and add him to my spam filter.