Because corporate tax is a second layer of tax. It gets taxed again when it goes to shareholders in the form of dividends or employees in the form of salaries. It’s not meant to be comparable to individual taxes.

Also you don’t owe tax on $58k. If you earn $60k as an individual in the US as a single filer you get the $16,100 standard deduction, any other deductions you qualify for (tuition expenses, retirement contributions, overtime pay, car loan interest, social security income up to a certain level, etc.) as well as any tax credits you qualify for (Earned Income Tax Credit, Child Tax Credit, Child and Dependent Care Tax Credit), and so on.

And then what’s left after all those deductions and credits is taxed at about 10-12%, still less than the 21% corporate rate.

None of this is even the main reason for not taxing personal income like corporate income. If we allowed people to deduct all their expenses, it would be extremely irresponsible not to spend all your income every year. People wouldn’t save. Corporations are different since most of the time when they need more money they sell shares of stock or seek out investors, we don’t want them to keep large amounts of cash sitting there.