Regressive doesn't refer to how the taxes are spent. Regressive refers to the fact that 15 cents out of every dollar matters a whole lot more to someone on minimum wage and living paycheck to paycheck. Regressive refers to the fact that a true "no exemptions" hits the poor more than the rich. So the left has to set aside exemptions for the poor, and that leaves room open for lobbyists to drive trucks full of money into adding more and more exemptions.
A 5% tax levied on everywhere to a lamborghini subsidy policy is regressive. It is important to look at both sides of the equation to make a conclusion.
Thats why you can have a flat tax, and a progressive government by spending for the poorer and levying flat. In fact, a flat tax is probably progressive simply because the rich dont use a multitude of public services the average poor does, like schooling, or healthcare or whatever.
Again, it is not economics to not look at how it is spent, because the spending can be progressive or regressive.
You can have super progressive taxation and a wealth distribution from the poor to the rich, and a super regressive taxation that distributes from the rich to the poor.
