(I suppose I'll rarely be making an exception of not investing the effort to post replies on this forum.)

Except you are calculating how much is paid in taxes incorrectly.

We use a progressive tax rate. Lets just use your examples. If you make 40,000 per year you are taxed at 4%. If you make 500,000 per year your income UP TO 40,000 is taxed at 4% (just like the guy that only makes 40,000) and the remainder is taxed at the higher rate.

This means the guy making 40,000 pays 1,600 and the guy making 500,000 pays (40,000 x .04) + (460,000 x .1) or 47,600.

Evidently you didn't pick up on the fact that this sort of detail's beside the point & that my objective here is to avoid getting sidetracked by these kinds of details, for those who don't like math or aren't good at it; I'm pretty sure that it's already a miserable headache for them as it is now. Why do you feel compelled to nitpick (LOL is that what the "N" in your name stands for, "nitpick"?) about this, especially given that in the OP, I included the parts that I have highlighted (with bold & underlined) below?

What's up with some (on the Left, to be specific) talking about wanting the wealthy - the top 1% (or 0.1% etc.) - to pay their fair share in taxes, then calling for their tax bracket rate to be something that's as absurdly high as 70%, maybe more?

When it involves brackets, it's dishonest to speak of some higher bracket as being a fair share; it makes no sense. A fair share tax rate is simply one that's the same for everyone; when it's a percentage, fairness is already built into it.

For example, let's take a 10% tax rate for everyone; if you compare what someone who makes $40k/yr were to pay in taxes to what someone who makes $500k/yr were to pay in taxes (and you have some basic math skills), you would discover (if you don't already know) that someone who makes $500k/yr is paying more in taxes than what someone who makes $40k/yr earns in a year.

If, for whatever reason, you don't know how to calculate this, I'll do it here for you; it's actually easy to calculate with the use of a 10% tax rate as an example, because all you have to do is move the decimal point and you don't even need a calculator:

10% of $500k/yr for 1 year is (10%) x ($500k/yr) x (1 year) = 0.1 x ($500k) = $50k

Is it fair that an individual who makes $500k/yr is paying more in taxes than someone who earns $40k/yr earns in an entire year? The individual who makes $500k/yr is paying $10k more than what someone who earns $40k/yr earned in an entire year, yet it's fair given that both pay the same tax rate, by a tremendously large factor of 12.5 to 1 ($500k/$40k = 12.5).

The fact that there are brackets means it already unfair in favor of the individual who makes $40k/yr. Suppose the tax bracket for the individual who earned $40k/yr is 4% instead of 10%; that makes the ratio a whopping 31.25 to 1 (that's (500 x 0.1) / (40 x 0.04) = 50/1.6 = 31.25).

This means that with a bracket rate of 4% for someone earning $40k/yr and 10% for someone earning $500k/yr **(BTW, the end result isn't that much different when taking into account the marginal difference, especially for those who make far above $500k/yr)**, for every dollar that the $40k/yr individual pays, the $500k/yr individual **is paying around $30.**

If the individual making $40k/yr doesn't think it's fair that they're only paying $4k in taxes (for a 10% rate) while the individual who makes $500k/yr is paying $50k in taxes, would they consider it fair if instead of that, the individual who makes $500k/yr were to only pay the same amount, $4k? Logically speaking, that can be considered fair.

I would expect someone like you, as someone who evidently knows their way around & is comfortable with math calculations to be aware of what the following example illustrates, but I'll cover it for those who aren't aware.

Let's take the hypothetical example of 40% as the highest tax bracket of $500k in a certain year; without getting into the details on what the lower brackets are and what the rates for each one is, let's suppose someone who made $500k (in that year) had to pay $60k in taxes for it. That's not too bad, right? It in effect comes out to 12%. Now, let's look at what the tax rate effectively comes out to for someone who made $20 million in that year; it's going to be:

$60,000 + 0.4 x ($20,000,000 - $500,000) = $60,000 + 0.4x($19,500,000) = $60,000 + $7,800,000 = $7,860,000 that they have to pay in taxes. That comes out to an effective tax rate of 39.3%.

For the individual who makes $500k, the ratio between 40% and 12% is about 1:3.333, but for the individual who makes $20 million, the ration between 40% and 39.3% is only about 1:1.018. What this means is that the more someone makes, the less significant, or the less it matters, that it's a progressive tax rate. The individual who made $500k only has to effectively pay a mere 30% of that 40% tax rate, but the individual making $20 million has to pay over 98% of that 40% tax rate.

Let's repeat the example, except with someone making $150 million, instead of $20 million; now things look like this:

$60,000 + 0.4 x ($150,000,000 - $500,000) = $60,000 + 0.4x($149,500,000) = $60,000 + $59,800,000 = $59,860,000 that they have to pay in taxes. That comes out to an effective tax rate of 39.9%.

For this individual who makes $150 million, the ratio between 40% and 39.9% is only about 1:1.0025. This individual has to effectively pay 99.75% of that 40% tax rate. The higher the income, the closer it gets to 100% of 40%.

Now the rates are not that dramatic and there are far more brackets.

Sure it's dramatic! Let's take a look at what the rates are based on this source (for unmarried individuals):

2018 Tax Brackets, Rates & Credits | Standard Deduction
It's simply a mere 10% for anyone who made $9,525 or less; on the other hand, the bracket's at 37% for anything over $500k.