43.4 million, over a third of all tax returns, resulted in the filer paying no taxes. In addition, since we're simply talking about federal taxes, any inclusion of local or state taxes has no bearing on the discussion, so, yes, I'd say he doesn't know what he's talking about either, at least in the context of this discussion as presented by yourself.
But, let's take this from the other direction - what FairTax does, aside from the largest re-distribution of wealth ever in this nation by giving out monthly pre-bate checks, brings 121 million people who presently have zero or negative tax liability. And it taxes their rent, their utilities, their gas - just about everything. And should it be implemented on January 1st, 2009, it will become the biggest political tool ever. Forget abortion, forget gay marriage - the winner will be whomever can state that they'd raise the monthly check the most, or reduce the at-register percentage of tax the most, who will 'reduce the taxes on milk by raising it on cigarettes', who will play the strongest game.
Yeah, the original author on this thread is right - this is the biggest liberal boondoggle ever. The supporters have a hope that this will bankrupt the US government and force a drastic reduction in government costs, but instead, it will be used to expand government to unprecedented levels. "But we can all have universal health care, just by raising the tax rate only one half of one percent in the months that end with 'y'. Will you say no to the children?"