Most developed western countries have a progressive income tax? But America?

Most western countries have progressive tax rate (charging as much as 50+% on income over $100,000 per year. For most earners it’s about 20 to 27% for earnings up to that threshold.

Income tax in Asia varies significantly by country, ranging from 0% in tax-friendly nations like Brunei to over 40% in high-tax jurisdictions, with most countries using a progressive system. Key hubs like Singapore and Hong Kong offer low rates, while China and India have higher, multi-tiered rates (up to 45% and 30%+ respectively).

In Africa?
varies significantly by country, with South Africa having one of the most developed systems, featuring progressive personal rates from 18% to 45%. Top corporate tax rates generally hover around 27%-30%, while countries like Chad, Ivory Coast, and Zimbabwe are among the highest taxed
Therefore America is an oligarchy
Please see attached images for more detail.
United States each state has its own state income tax; 7 states have no state income tax
The federal income tax is charged in addition to state income taxes and is simplified as follows
Tax Brackets (2025/2026): The seven rates are 10%, 12%, 22%, 24%, 32%, 35%, and 37%. For single filers, the 10% rate applies to income up to $11,925, while the top 37% rate applies to income over $609,350.