SS&medicare tax (at a lower proportion than the rich), etc.
Actually, payroll taxes that go towards SS and Medicare stop at 106k, meaning after your first 106k, you don't pay them.
Those programs are also the major gripes by people, so it's nice to keep in mind that the poor people
are paying for their "entitlement" programs.
The point is, there are more federal taxes than just the "income" tax, which Americans pay. The oft-used number that many people don't pay federal income tax is misleading, as that article thoroughly demonstrates. People who don't have money can't pay taxes on that money, and that's the simple truth of it.