Are low taxes about moral desert (or freedom)?

Ned Resnikoff criticizes (what he perceives to be) a reliance by conservatives on moral desert for their tax-cutting arguments.  Does the hard-working billionaire deserve more than the hard-working waitress?  What about the billionaire who inherited all his money?  Etc. etc.  He concludes that tax policy should "balance the state’s ability to provide needed services for all citizens, including its most needy, while preserving a capitalist system which rewards achievement, and therefore (one would hope) innovation, productivity and excellence."  I tend to agree with Resnikoff's conclusion, but I think he mischaracterizes mainstream conservatism's tax arguments.  He writes:

The only thing this debate about who deserves what really tells us is that very few people are willing to admit just how insubstantial and malleable our innate character really is. When you control for environmental, genetic, social, historical, and biological factors, what differentiates my own distinguishing features from Charles Manson’s -- or, for that matter, Obama’s, Palin’s, Lincoln’s or yours -- is either imperceptible or completely nonexistent. And if that’s the case, I don’t see how you can argue that either of us deserve more or less than any of those people.

What this suggests to me is that the only way you can coherently argue that a person inherently deserves a certain level of privilege or material comfort is to also argue that all persons deserve it, by virtue of their personhood. We already have language to describe these things that all persons innately deserve: we call them rights.

I find his degree of determinism a bit disturbing, but I think he also misses conservatives' main point.  I don't think most conservatives focus on moral desert as the linchpin of tax policy.  I think they focus on freedom.  They're not the same thing.  (I think economic freedom tends to get overplayed by conservatives, but that's another story . . .)