Regressive in the context of taxes means the rate of taxation increases while the base used to calculate the tax decreases. For example, the payroll tax is regressive. That is, the less you earn, the higher percentage of payroll tax as a ratio of income. Payroll tax is the tax, income is the base.
Under the nrst, taxes are based on spending, not income.
Someone who spends less will have a lower rate. That is not regressive. In part this is due to the rebate function of the nrst (which I could do without).. But to be clear, the nrst (as proposed in HR 25) is not regressive.
Quick! Send everyone an NRST entitlement payment to level things out!