Are you implying that the holders of green cards shouldn't be required to pay taxes?
Perhaps more than that even.
The first things I wonder about are "Who pays taxes; how are those taxes paid; and what percentage of the individuals income goes towards paying those taxes?"
These are regressive taxes, meaning poorer people pay a greater % of their income in such tax then richer people for the same item at the same price.
Are poor people equally represented? Are there any barriers that might keep the poor or non-citizens that still must pay taxes and in fact pay a greater % of their income in taxes from having representation?