Did you read this part of the article?
Shouldn't everyone have some skin in the game?
Besides, the real argument is that you would never in a million years get the congress to give up their ultimate power base, and accomplishing this would take an act of congress as the POTUS does not have the power.
A flat tax is, by definition, NOT regressive. It’s not progressive. It’s — DUH — flat. The author is an economic illiterate.