Not only that it's an oxymoron. There is nothing fair about the fair tax. It's just another stupid ploy the wealthy hand out there to the numerically and financially illiterate who don't understand that regressive taxation is NOT in their best interest unless they are very wealthy.
There isn't really that much wrong with our current tax code other than that it is far to complicated and that it permits those with enough money to hire enough tax lawyers, accountants and lobbyist to get out of paying what they owe. From a fairness standpoint our current system is pretty fair.
Progressive taxation is the only fair form of taxation cause those who control the most wealth and income should pay most the taxes. That is to say, if 10% of the population control 90% of the wealth, than they should pay 90% of the taxes. If you look at a break down of our system in terms of income earned and taxes paid you'd find that the distribution is really quite fair. In fact part of the income inequality we are seeing in our nation is that unearned income, that is income of dividends, interest and capital gains are not taxed progressively. For the highest 20% of income earners due to low taxes on unearned income and because a substantially higher portion of their income is derived from unearned sources which is taxed at a far lower rate. The end result is that someone at the bottom of the top 20% earning about $250,000/year is paying around the same affective income tax rate as someone making $2,000,000/year.
I've argued before that the low tax rates for unearned income sends the wrong message that unproductive wealth is more important than productive wealth. That earning wealth from dividends, interest and capital gains is of greater value than wealth that is produced.
If we really want to make our tax system more fair we need to end the favored tax rates of 15% for capital gains and other sources of unearned income and return it to the 28% level or we need to get rid of the capital gains tax period and consider all forms of income as personal income to be taxed at the personal income tax rates. This way Billionares don't end up paying a lower affective tax rate than their secretaries. Besides, the capital gains tax is bases on a false premise. That taxation discourages investment. That's a mythology that has been debunked a long time ago. So by simplifying the tax code and getting rid of the loopholes and special tax rates for those whose earnings are based largely on investment we go a long way towards making our current system of taxation even fairer and would do so with out raising the current personal income tax rates.
Flat taxes and other regressive schemes are idiotic and are usually supported by either proles who can't do basic math or by those, like you, who make large incomes off of investments who want to manipulate morons into lowering his tax burden even further.