I don't know if you intentionally sabotage your own argument by posting links to those sites, or if you really aren't aware of the self-interest behind their reports.

I don't know what argument you are trying to make. You dislike the Brookings Institute (the original source of those #s), therefore the numbers I cited are wrong?

These numbers are picked over to distort the conclusion. They include in total tax burden the estate tax but not the sales tax. That's funny in a "haha I dropped my monocle in my brandy again" sort of way but not in a way that's useful for evaluating tax policy.

Sales tax? I'm not from US but what sales taxes would individuals, particularly poor, be paying? Typically sales taxes are on businesses (where I live, we have value added tax, which is a further development of that, designed to distort the value chains less).

In the US, "sales tax" refers to an additional percentage charge added to the retail prices of goods and services. It's a terrible system, but individuals (poor or otherwise) might pay it for just about everything they buy: clothing, restaurant food, tools, repair services. It's collected by the retailer at the time of sale, who then reports it and passes the amount collected on to the state. Sometimes cities and counties have additional taxes, normally smaller than the state does. There is no federal sales tax.

Depending on locality, combined state and local sales taxes are typically in the 7-10% range, and unlike a VAT are only charged by a retailer who sells to the final user of the product. Business that resell products are exempt (after filling out the proper forms) until they sell to the final consumer. Also unlike a VAT, they are almost always in addition to the posted price --- if an item is marked as $5, you will be charged $5.54 (or some such). Despite the exemptions, sales taxes are generally end up being "regressive", in that the poor tend to pay a greater percentage of their income as sales tax than the rich.

Each state has it's own convoluted laws for what is taxed and what is not. Frequently, "essentials" are untaxed, while most other items are taxed at the same rate, but no two states agree on what is considered an essential. One state might never charge for food items, another might charge only for ready-to-eat food, and another only for food consumed on premises (unless it's cold, a breakfast beverage, or above a certain size). It's a mess, getting it right as a small retailer can be difficult, but the penalties for failing charge and collect the correct tax can be strict.

Unless you believe the poor are paying 32.6% of their income in sales taxes it won't change the conclusion. (Google suggests the highest sales tax is 9.45% in TN.)

You must be so happy to have discovered that the USA really is as progressive as you always wanted it to be.