One thing you didn't bother mentioning is that the brackets are marginal. You pay the same % in tax on your income as you move through the brackets.
So your tax rate from 0 > 50k is different than your tax rate from 50>100k, is different from 100k > x, etc. etc.
The AGI is just the average tax on all the income and is misleading when used in the way you've used it.
It is fairer than you claim it to be. Wealthy people pay the same tax burden on their first 'x' dollars as a poor person. They simply pay more within the next bracket.
Your numbers also do not account for clever tricks in accounting. A person making 300k/yr is only going to be taxed for, essentially, 287.6k due to standard deductions (or thereabout).
People in those tax brackets pay accountants, tax professionals, and even utilize tax havens and shell companies to hide their money.
Do you think the average person making 60k/yr is spending a few grand to save a few grand? Of course not.
But someone making 300k is willing to spend a few grand to save 10s of thousands by using itemized deductions, loopholes, parking mechanisms, etc.
Besides all of that, the problem people have with the current tax system is that the BURDEN of having to pay taxes is not fair.
Someone making 60k, paying ~7% of their income in taxes, is hurt and stifled far more by that 7% than someone making 200k paying an average of 14-17%
200k paying average of 15% still makes 170k/yr after federal tax.
Someone at 60k will only bring home ~55000.
Try living on 55k. Then try living on 170k. Tell me which one you think is easiest.
$4.5k goes a lot further for a person earning 60k than 30k does for 200k/yr. The struggle is far more pronounced between those two.
Then look at the super wealthy. You're bringing home 1.6 million dollars and pay ~25% (assuming you aren't utilizing trickery to further reduce that to zero) means you are STILL making 1.193 million.
Do you think that the person taking home 1.193m is now struggling because they paid a total of 400k in taxes? lol
Sorry, but I don't buy it. This is similar to how traffic tickets work. You get a ticket that is supposed to be a punishment and deterrent, yeah?
You ticket a person making 40k/yr $300 for not having their tag up to date (or something). That can destroy that person's life for an entire year. They definitely won't want to deal with that.
But a person bringing in 200k a year? Do you think a $300 ticket bothers them? What about a person making 1.16m? You think they'll really care? Does that destroy their life?
Of course not.
This is an issue of tax burden. The burden it places on your ability to feed, clothe, house, and care for your family is what this all boils down to.
And please, feel free to add the tropes "go back to college" or "find a better job" or "these were your life choices" or "those people making more money work harder" (a lie). I know someone will want to regurgitate those silly sayings that were brought to you by the people in the top brackets.