That is a poor definition of a regressive tax. A better definition is "a tax that ignores the marginal utility of income in its application".
Poor people derive overwhelmingly more value from dollar $10,001 than rich folks do from dollar $1,000,001. (This is not controversial.) Thus, rich folks can--and should because they derive more value from the structures of the society that enables them to be successful and not hit over the head for their paycheck--pay progressively more to sustain that society. (This is also not controversial in reality, even amongst relatively right-wing economists.)
The marginal utility of income is not measurable, whereas the percentage of income that gets paid as tax is. That's why "regressive" and "progressive" taxation is defined in terms of the measurable thing, not the unmeasurable thing. What you're saying is simply that a progressive tax system is better because it attempts to take into account the marginal utility of income.
And then everyone starts arguing about how progressive the system should be to do that properly. :-)
The definition I gave is, nonetheless, the accepted definition of the term. Can't find a citation for yours.
(Note: I do understand about utility, and how/why progressive tax systems help society. My only bone of contention here is that you're trying to redefine a specific term to have a different meaning.)
"While a flat tax imposes the same tax percentage on all individuals regardless of income, many see it as a regressive tax. A regressive tax is on which taxes high-income earners at a lower percentage of their income and low-wage earners at a higher rate of their income. The tax is seen as regressive due to a more significant portion of the total funds available to the low-income earner going to the tax expenditure. While the upper-income payer still pays the same percentage, they have enough income to offset this tax load."
ISTM a system that differed from the current one by really "closing all loop holes" would be significantly less regressive. Of course, there isn't a snowball's chance in hell of that actually happening in our Congress, but the vision is admirable even if isn't practical.
Actually, no it's not. The poor are taxed at the same rate as the wealthy. Regressive, is that they are taxed more.
I'm suggesting that we take substantially more from the ultra wealthy; many of whom already pay <15% tax. I'm also suggesting we tax the middle class less as well (who often pay more by percentage >15%) and the poor don't pay taxes until after they make a "live-able wage", i.e. only after they can afford food and shelter do we tax.
A flat 20% tax rate, plus removing loop-holes or tax refunds would dramatically impact the wealthy and middle class. Then we drop taxing the poor (which the U.S. already does).
I think it's naive to think we should just "raise taxes" to disproportionately take from the people who have money. They may have earned it, I don't want to take their wage, any more than I want to take from someone who works in the field all day.
The income tax would not be regressive, but the overall tax system (including sales tax, gas tax, and other consumption or usage taxes) would be regressive.
That isn't to say that regressivity is a fatal flaw — tobacco taxes and other "sin taxes" are all regressive, but they're seen as good because the goal is to discourage behavior, not raise revenue.
By definition, the tax system in the post you replied to is not a regressive tax system.