By being a part of US society (i.e. being a citizen), you're automatically expected to contribute monetarily to the well being of the citizens of the US (and your state/country/city) as a whole, whether you agree with it or not. It's why you have access to things like safe drinking water. Regulated quality food. Cars that don't explode as a standard. And so forth.

And it's the same for every country in this world.