NightFox
Wildling
You quote a lot of things but you show nothing
It's quite simple, government is funded by taxes. If you have a progressive tax system and replace that with a flat tax system that means the poor pay more and the rich less and that inceases income inequality. Unless you're an anarchist and want to abolish government of course, then you don't need taxes anymore.
Nothing wrong with supporting that, just don't be so hypocritical about it. Just admit that you love the 1% and hate the poor.
You may not being looking at this question from the proper angle, first off understand that "the rich" absolutely LOVE our current tax system and why wouldn't they? they created it. They have the money, power and connections to basically write any tax system they want, what they've done is created a system that is so full of loopholes, exemptions and credits that only they have the means to engage the necessary legion of lawyers to take full advantage of it, they also get the added bonus of being able to point to top marginal rates (which they never pay) and say "See! look at how high our income tax rates are!". Proponents of so-called "progressive taxation" in the name of fairness are actually advocating a system that is designed to be anything but "fair", it's a system that the average tax payer can never in their wildest dreams play on a level playing field in and it's a system that treats their dollars as less valuable then the dollars earned by those farther up the economic ladder.
A flat tax on the other hand is far more expensive for "the rich" in terms of real dollars, goodbye loopholes, goodbye exemptions, goodbye credits, goodbye playing games with income timelines, goodbye economic behavior manipulation, that's not what they want because it's actually "fair" since it treats every dollar they make exactly the same as every dollar everybody else makes. As far as the poor go it would be counter productive to tax their income at all, people below the poverty line require a flat income tax rate of 0% since taxing their income is a roadblock to getting them to where everybody wants them to be (above the poverty line). Keep in mind that if "the rich" really wanted a flat tax system, we'd have a flat tax system post haste because they're the ones that are really calling the shots right now but they don't want it which is the reason that we probably aren't ever going to get it.
Lastly just imagine what we could do without having to waste the billions of man hours that go into tax preparation & enforcement every year, if that labor actually went into something PRODUCTIVE.