> I explained that anything less than a progressive tax was going to make the poor pay more and the wealthy pay less.
Here's a formally-verified proof in Lean that with a flat tax, if you have more income, then you pay more tax: https://live.lean-lang.org/#codez=JYWwDg9gTgLgBAWQIYwBYBtgCM...
The theorem uses one important assumption: that the flat tax rate is positive.
I believe everybody understands that a percentage means exactly that.
But if you account for minimum living expenses M, if you are under M, 30% of M is "more" than if you are at 10x M for the quality of your life. What scheme is "fair" is harder to figure out, though.
Yes, I object to that type of language too, but let's not ignore the context.