If you live in this country, and you benefit from the opportunities of being an American, then you have to look at the nation as your family. To keep a roof over the head of a family, people in the family need to work, and pitch in toward providing that roof, as well as other things necessary for survival such as healthcare, food, transportation, etc. In order to pay those bills, different working members of the family pitch in a portion of their wages. Those who make more, can typically pitch in more.
Obviously people have different opinions on this topic, and it's clear that you have a differing opinion from drew and corked7. So there's never going to be a resolution or agreement in this argument.
How far do you take things though? Is money simply to remain with a family in your opinion? What if your parents cut you off at 18, and kicked you to the street. What if they said "this is money that I earned, and you aren't getting any of it, get your own, the only way you can stay here is if you work and pitch in". Well that's what your American family is saying to you, if you want to live under our roof, you pitch in.
If America goes down, you go with it. If you want to be a member of the American family, you contribute.
I understand your point of view, and why you think that everyone should pay exactly the same, but things wouldn't work if that were the case.